Polly stepped into the console room and looked around at her two companions. Ben was polishing his boots in the corner. The Doctor was standing by the console, watching the up and down movement of the time rotor with one eye and, with the other, reading from a thick, leather bound book.

“Your five hundred year diary,” she observed. “Are you looking something up? Something that happened in the past?”

“I’m looking at something that is about to happen in the present,” The Doctor replied. “The future isn’t yet written. The pages are blank. Except for a few lines.”

He gave the diary to her. Polly looked. The pages he had opened it at were blank, except for one very short paragraph.

“Ben finished polishing his boots just as the TARDIS materialised on the watery planet of Crann. He put them on, ready to face the adventure ahead.”

Polly looked up. Ben was fastening the laces of his boots. The time rotor wheezed a few more times then there was a slight bump almost like the bump a train makes when it stops at a station and the forward momentum causes the carriages to run into their buffers.

“We’ve landed.... on the watery planet of Crann?”

“The TARDIS’s rickety old instruments can give false readings. But the diary tells the truth,” The Doctor told her. “Put your coat on, my dear. It might be a little breezy outside.”

Polly took her coat from the hatstand and slipped it on. By the time she did so The Doctor had opened the door. Ben stepped out first, then Polly, and The Doctor came last, locking the TARDIS door behind him.

“Oh, it’s pretty,” she said as she looked around. “It’s really, really pretty. Look at all the little islands all joined together by wooden bridges.”

There were seven of them, at least as far as they could make out. Six were arranged in a rough hexagon around a central one. There were long, narrow bridges of rope and wood from the central island to the others and bridges joining them to each other so the arangement was like a wheel with a hub joined to the rim by spokes. The TARDIS had landed on one of the spokes, halfway between a rim island and the hub. Ben and Polly looked over the side and saw deep but beautifully clear water like a coral lagoon. There were fish of all sizes swimming around in the water. They didn’t look like any species they recognised, but they were clearly fish.

The islands were all surrounded by fences some seven feet or so high, but on the hub island there were roofs of some kind of matted fibre to be seen above them. Smoke rose up as if from cooking fires. They were obviously inhabited islands.

“Of course!” The Doctor exclaimed triumphantly. “Crann.... Crannog is an old Celtic word for an artificial island. The ancient but industrious peoples of your world built them... most especially in Ireland and Scotland. Man-made islands in the middle of lakes with houses, barns for livestock, even gardens growing food on some of them.”

“Why?” Ben asked. “Seems like a lot of hard work to me.”

“Protection,” Polly guessed. “In those days, there would be Vikings or some sort of invaders coming all the time. If they pulled in their bridges they’d be safe. Even if the enemy rowed over they’d have time to pick them off.”

“Perfectly correct, Polly,” The Doctor told her. “Well done. But by the looks of things, this group of crannogs isn’t in a lake. It seems to be in an ocean. Look.... that must be another group of them in the far distance. Do you see?”

Polly and Ben both looked across the wide expanse of blue water to a dark smudge that might well have been another group of islands. Then The Doctor pointed to another one. And another. The ocean was dotted with small groups of man made islands.

Man made? Ben and Polly both thought the same thing at once. This was clearly another planet. The blue sky had three big moons hanging in it even in broad daylight. So could the people who made these islands and who lived upon them actually be called men? Would they look like men as they knew the word?

That question was answered moments later. A doorway opened in the tall wooden fence that surrounded the hub island. A group of six tall, slender men came out. They looked Human. They wore jerkins and loose trousers made of something like chamois leather and their faces and arms were tattooed with blue symbols. One, who seemed to be a leader, was completely bald with tattoos all over his scalp. He stepped forward as his men kept sharp-looking spears pointed at the time travellers.

The Doctor stepped forward to meet him. Ben glanced around and noticed that more men had emerged from the nearest rim island and were closing in behind them. If they were going to run it would have to be in the next few seconds before they were cut off from the TARDIS. He didn’t fancy their chances of fighting through that many.

“We come in peace,” The Doctor said, opening his arms with his hands palm upwards to show that he had no weapons. “My companions and I are travellers from another place. We mean you no harm.”

“Travellers?” The leader seemed to be turning the word over on his tongue as if it was new to him. “You are not shadow men... Are you friends?”

Friends?” The Doctor smiled widely. “Oh, yes. Friends. Definitely. Absolutely. No question about that. We’re friends. I’m The Doctor. This is Ben and Polly. Friends.”

The men behind them had surrounded the TARDIS. They were touching it all over, reaching to press hands against the little windows and stroke the wooden panels. They seemed excited by it.

“It’s blue,” Ben noted. “They like it because it’s blue. Blue seems to be a special colour for them.”

That certainly seemed to be the case. More of them were crowding around the TARDIS. It was rocking slightly from their pushing and prodding at it.

“Oh my, oh dear me, oh no,” The Doctor groaned. “Oh, don’t do that. The TARDIS is very precious. Please be careful.”

The leader looked at The Doctor and then at the TARDIS. then he raised his hand.

“Friends who come in peace, enter,” he said. “Precious blue will be carried in reverence.”

“My thanks,” The Doctor said in reply. “Come along, Ben, Polly. We have been invited into their home. We shall respect their customs.”

“Unless any of them involve cannibalising guests,” Ben added. Polly shot him a worried look. The Doctor patted her on the arm reassuringly.

Cannibalism clearly wasn’t a feature of the Crannog dweller’s lifestyle. They might all have looked plumper if it was. The people within the hub island’s walls were all, male and female, old and young, stick thin. She looked at them at their work or sitting by cooking fires outside their little houses made by something like the ‘wattle and daub’ method she recalled learning about in history books. They seemed to be healthy, though. She concluded that it was a racial trait that made them thin rather than malnutrition.

The leader brought them to his own house, a slightly larger one than the others. The TARDIS was manhandled into place beside it before he dismissed the men who had carried it and turned towards a thin woman, tattooed in blue, who sat by the cook fire with a baby in her arms and a toddler by her side. She smiled warmly at the leader and then shyly at The Doctor and his companions.

“These are friends, Marissa,” the leader said to her. “They come in peace with the precious blue to pay us honour.”

“Friends are welcome, Marton,” she replied then invited The Doctor and his companions to join her by the fire. They sat on woven fibre mats. The Doctor seemed completely comfortable like that, crossing his legs in front of him and smiling brightly at everyone. Ben didn’t like sitting on the floor because it seemed to him a long way back to standing if he had to fight. He felt slightly vulnerable. Polly just felt a little self-conscious when she realised that the women all wore chamois skirts that reached their ankles and she was in a knee length dress. She tucked her legs under her as she sat.

“We are eating now,” said Marissa to them. Her husband, leader of the community though he was, did his share of housework. He brought carved wooden bowls and a loaf of some sort of bread on a board. He cut the bread while his wife poured stew into the bowls and gave it to their guests first.

The meat in the stew was white with a slightly rubbery texture. The Doctor didn’t express any opinion about what it was. Ben and Polly conducted a sort of mime between them in which Ben suggested it was a sort of squid and Polly wrinkled her nose at the idea and transferred most of the meat into Ben’s bowl, drinking the vegetable broth that remained and chewing on the bread that had the taste of something like barley.

“It is almost dark fall,” Marton told them as they finished the meal. “Will friends join in our homage to the sun?”

“We will,” The Doctor said on everyone’s behalf. Marton left the fireside. As tribal leader he clearly had preparations to make. Marissa began to pick up the empty bowls. Polly offered to help, but her reply made it clear that guests did not help with housework. They were left by the fireside as their hosts went about their business.

“They seem nice,” Polly said when they were alone. “The people... the Cranns... I suppose we could call them.”

“They’re a little bit worried,” Ben commented. “Not about us. They obviously accept that we’re friends. But, Doctor, remember what Marton said when he saw us.”

“‘You are not shadow men’,” The Doctor quoted. “Yes, yes, indeed.”

“Shadow men?” Polly queried. “What does that mean?”

“I should think they are the reasons for the high fences. The equivalent of the Vikings you mentioned earlier, my dear.”

“Oh dear.” Polly thought about it a bit more. “Do you think that these Shadow Men look different to us... or them?” she concluded. “They knew right away that we weren’t them. So... maybe they’re a different species. Reptiles or fishmen or something.”

“They must be sort of like us,” Ben pointed out. “Since they said ‘men’. But I think Polly is right. The Shadow Men must be different.”

“There are many species that come under the broad category of humanoid,” The Doctor explained. “Strictly speaking only those who come from Earth or are descendents of settlers on Earth colonies are called Human. Everyone else – even my own race – is called humanoid. Though that doesn’t mean your race is the first or the most superior. You are simply the most widespread - just like the brown rat which is seen so commonly that its proper name is Rattus Rattus.”

“Er....” Ben looked at The Doctor and wondered if his species had just been insulted.

“The Cranns.... they’re not Human colonists, surely?” Polly asked. “Colonists would have come in space ships and they’d have things like electricity and computers?”

“There are many colonies where the people, having arrived by means of technology, then abandoned its trappings and returned to a simple life, living off the land,” The Doctor pointed out. “But in this case, I believe you are correct, Polly. The Cranns are not related to Earth Humans. They evolved separately on this planet. I think it quite possible that there was more dry land a long time ago. These crannogs were their method of coping with rising sea levels. Do you notice, the rim crannogs are not inhabited. Some of them are farms. They grow enough grain for the bread we ate at supper and the vegetables in the stew. The others are arboretums. They grow trees.”

“Why?” Polly asked.

“Because trees are what the crannogs are made of,” Ben answered her. “Everything is wood from the bowls and spoons to the spears, the walls, the floor under their feet. They need trees to make new crannogs and maintain the existing ones. That’s right, isn’t it, Doctor?”

“Perfectly correct. The main bulk of their food, of course, comes from the sea. Plenty of fish to be caught. A monotonous diet, perhaps, but more than adequate. They have a good life in all respects. Except for these Shadow Men. And you are perfectly correct about that, too, Ben. They do fear them.

The sun was going down fast. The three moons brightened in contrast. Two were silver and the third one a coppery colour. The crannog dwellers gathered together and for the first time it was possible to count their numbers. There were perhaps two hundred of them in all, men, women and children. They gathered for a simple rite that acknowledged the coming of night, the end of the busy working day. It ended as the sun set completely, and the people went back to their little homes. Marissa brought Polly back to her home along with the children, but The Doctor and Ben went with Marton to see the night watch. They steppe through the gateway onto one of the spokes of the crannog wheel and across to the nearest rim crannog.

It was an arboretum, as The Doctor had said. Within the fence trees grew close together, vying for the artificially created soil for their roots and the sunlight on their canopies. There was a clear space all around the copse, though, and crannog men kept vigil on the path. They carried flaming torches to see their way, but The Doctor noticed that they kept them down below the level of the fences.

“Most of the cooking fires are out, now,” The Doctor told Ben. “And the torchlights are kept low. They want to make the crannogs as near invisible in the night as possible.”

“The Shadow Men attack at night,” Ben concluded.

“Just so. Though it cannot happen every night. The level of fear is nowhere near as high as that. It’s not like London in the Blitz, for example. They live with the possibility of attack not the imminence of it.”

“The way we live with the possibility of atomic bombs in the cold war?” Ben suggested.

“An appropriate analogy,” The Doctor agreed.

It took nearly an hour and a half to walk the whole rim before returning to the hub. Looking back across the spokes the outer crannogs were outlined against the starry sky, but from out at sea they would be virtually invisible until a boat was almost upon them, and by then, the watchers should have spotted the approaching enemy.

Marton brought them back to his little house. Inside it was a haven of peace. The two children were asleep, now. Marissa was sitting on a mat weaving a piece of cloth at a hand loom. The room was lit by small, round tallow candles that floated in wooden bowls of water. They were sufficient to work by and with the woven fibre door pulled across none of the light spilled out.

Polly was attempting to weave, too, but it wasn’t working for her. She gave up in despair.

“It’s no good,” she said. “I can’t do this at all. I’m just wasting the yarn. It’s too precious to you for me to do that. But... please... won’t you tell The Doctor what you were telling me before... about the Shadow Men.”

Marton looked at his wife. His expression was a mixture of shock and embarrassment.

“Marissa, this is not talk for friends... for travellers...”

“Please,” she answered him. “Tell... tell them... friends can help.”

“We can,” Polly assured them both. “The Doctor can. He can help. He is good at helping people. It’s... it’s what he does.”

The Doctor reached out to Marissa and held her hands.

“Yes, I can certainly help. If you tell me what the problem is. Marton, don’t be afraid. You can trust me. Please tell me...”

“They come in the dark... and take men,” Marissa said. “They take men... into the sea. They never come back.”

“How many men? How often does it happen? What do they look like?”

That was too many questions at once. The Doctor had to go more slowly and carefully. But little my little he managed to find out that they had seen about a dozen of the Shadow Men the last time they attacked. They always came at night, which was why the watch was so vigilant. It last happened to their community three years ago, but they knew that other Crannogs were attacked from time to time. They always took men, young, strong men.

“For slaves, I suppose,” The Doctor murmured as he took in those details. “But... what do they look like?”

“They have a shape of men,” Marissa said. “But they are just shadows... black shadows. No faces... No eyes...”

“If they have no eyes... how do they see?” Polly asked. But Marton and Marissa could not tell them that much.

“My brother... he was taken...” Marissa added. “The Shadow Men took Mallik... I saw them...”

It was clear it was distressing to her. The Doctor spoke kindly to her and she thanked him for that.

“My brother... must be dead, now,” she said. “None ever return.”

“Where do the Shadow Men come from?” Ben asked. “There’s no land as far as we can see, only the crannogs belonging to people like this.”

“Yes, that’s a puzzle,” The Doctor agreed. “Let me think about this. If the people knew more about the Shadow Men, they could do more than defend themselves against random attack. They could fight back.”

“We are not warriors,” Marton said. “We grow food. We build. We fight if we must. But to attack... that is not our way.”

“So you’ve just put up with this... for however long?” Ben was appalled. “I wouldn’t stand for it. If I saw one of these Shadow Men I’d give him a good pasting.”

“I’m not a man of violence usually,” The Doctor admitted. “But I think in this case, it is necessary. But there is no sense in any action until you know your enemy’s strength, and its base of operations. As I said, let me think about it.”

“Please, be at peace here this night,” Marton said, indicating that they should be his guests overnight and that plans to fight the Shadow Men could wait until daylight. The Doctor agreed. There was little to be done in candlelight in any case. He accepted a bed upon a thickly woven mat with a softer rug over him for a blanket. Ben and Polly both settled down, too, along with their hosts. The candles burnt low and went out and it became very dark in the little house.

It was several hours later when they were woken by a cry of alarm. Marton rose quickly as a man with a torch came to tell him that the crannog was under attack. Marissa went to the children as her husband ran to join the defence.

“Where’s Polly?” The Doctor asked as a relit candle’s light spread. “Where is she?”

“I think she went to the TARDIS,” Ben answered. “She... wasn’t too keen on what passes for a bathroom around here. She went to... you know.”

“I’ll go and make sure she’s all right. Ben... look after Marissa and her little ones while her husband is busy. This could be your chance to give a Shadow Man a pasting.”

Any other man might have regretted those words. But Ben had meant it. He was ready to fight. The Doctor left him to it and stepped outside.

There were a lot of torches lit, now. There was no point in trying to be invisible now that the Shadow Men were attacking.

They had obviously crept through the night in long, low boats. One of the boats had actually got through the rim defences and was in the lagoon between the crannogs. The Shadow Men had climbed up onto the bridges and moved stealthily before the alarm sounded.

There were only a dozen of them, but they were strong and fast and they had weapons that felled the Crann men before they got close enough to use their spears. They seemed only to stun, not kill, because the victims were grabbed and pulled down into the waiting boats.

All this The Doctor noted in the torchlight. He noted, also the screams and cries of terrified women and children and the anguished shouts of men who were overpowered by the enemy.

He noted, also, the exact nature of the enemy. He recognised them silhouetted in the torchlight. Shadow Men was certainly an apt description of them, but he knew them of old by a different name.

“Polly!” he cried, remembering his mission. He turned to the TARDIS and stepped inside quickly. He found Polly inside, staring at the viewscreen in horror.

“Oh, Doctor! What are they?” she asked. “What do they want?”

“They want men,” The Doctor answered. “Not women or children. Just men. I wondered about that last night when Marton and Marissa explained. And now I see it... Yes, they only take young, strong men.”

“They’re taking Ben!” Polly screamed in horror as she saw him being carried out of the house over the shoulder of one of the Shadow Men. He was unconscious, stunned by the weapon. The Doctor wondered if he had managed to give any of them a ‘pasting’ after all and found himself hoping he had.

“They’re taking the TARDIS!” The Doctor exclaimed in horror as the console room rocked alarmingly. On the viewscreen four of the Shadow Men had surrounded the police box and were pushing and manhandling it away. Polly ran to The Doctor and he held her as the TARDIS lurched suddenly. It had been pushed right over into the lagoon. They slithered to the floor and then slid around onto the wall as that became a floor. The TARDIS was floating on its side. The Doctor and Polly saw one of the Shadow Men actually sit on top of the TARDIS as if it was a raft. Ropes were thrown around it. The TARDIS was towed on its side, out to sea behind two of the Shadow Men’s rafts.

“Doctor... what are we going to do?” Polly asked. “This is terrible.”

“It’s not exactly what I planned,” The Doctor admitted. “But in many ways, it fits in very well. I suspect we’re being taken right to the Voord city.”

“The what?”

“Voord. Oh, yes. That’s what they are. Voord. A semi-aquatic race with telepathic skills and rather a nasty temperament. I came across them quite a few years ago on a planet called Marinus. But I suspected they weren’t native to that world. I don’t imagine they’re native to this one, either. They’re scavengers, stealing technology.”

“Stealing people,” Polly corrected him. “This planet doesn’t have any technology.”

“Indeed. Which makes me wonder... Mmm. Yes, indeed. There’s something.... something else here. Something I haven’t understood yet. But we’ll know more when we get where we’re going.”

“No, we won’t,” Polly told him. “We’re captured, don’t forget.”

“We’re not. The TARDIS is. They don’t know they have us.”

“Oh... good point. So... we just lie here and...”

“Enjoy the ride,” The Doctor said mildly.

The ‘ride’ lasted nearly an hour. It was almost dawn, though not quite. It was still dark enough for the Voord on top of the TARDIS to look like no more than a dark shadow against the sky. But they had obviously reached their destination. Three of the Voord boats with their captives were gathered in a circle along with the TARDIS. In the middle of the circle the sea began to bubble and agitate and something broke the surface. It was shaped like a domed tower. A wide door slid open and the Voord rowed their boats up into it. The TARDIS was pulled inside as well. Then there was a sensation of downward motion.

“It’s a lift,” Polly said. “We’re going down.... underwater. The Shadow Men... the Voord, I mean... they have an underwater base. That’s why we couldn’t see anything.”

“I suspected as much,” The Doctor said with a smug look. Then the downward motion stopped. “Uh oh. Hold on, my dear. They’re turning us upright again.”

The TARDIS tipped and Polly and The Doctor slid down the wall again onto the floor. The Doctor went straight to the console. He read the environmental controls and reported that they were some two hundred feet below the surface of the ocean. He looked at the viewscreen. They were obviously at the bottom of the lift shaft. The boats were high and dry now. The water had drained away. The Voord climbed out and brought their unconscious prisoners with them. The TARDIS followed, shoved along by four of the Voord.

“Oh, they have Marton, too,” Polly noted as they watched. “I didn’t recognise him before. Poor Marissa. First her brother, now her husband. How cruel.”

“There’s Ben. He looks all right.”

“When we get where they’re going and the guards leave, we can grab him. We can grab them all and get them into the TARDIS. They’ll be safe."

But at a junction of corridors the TARDIS was taken to a different place than the captives. They lost sight of them.

“Don’t worry,” The Doctor assured Polly. “We’re not finished, yet.”

“I wonder why they wanted the TARDIS, though. They can’t possibly think they can use it.”

“They can’t. They won’t even be able to get into it. They tried the last time. It fascinated them, though. They’re telepathic, and the TARDIS’s own telepathic circuits attract them like a honeytrap.”

That seemed to be the case. The TARDIS was brought into a room and the Voord gathered around it. They touched it as enthusiastically as the Crann people had done. Except, if The Doctor was right, their fascination had a different cause.

“What’s that noise?” Polly asked turning from the viewscreen to the console, which was emitting an unusual low hum. It was like a buzzing of bees.

“It’s the Voord trying to communicate with the TARDIS,” The Doctor said. “Wait... I have an idea.”

He dashed around the console, pressing buttons manically. Polly looked at him curiously, wondering what he was up to.

“I’m looping the telepathic signal back around and augmenting it,” he said. “Feeding it back to them at the telepathic equivalent of 10,000 decibels of sound. It should stun them.”

With that he pressed a final button. Polly put her hands over her ears as the buzzing sound increased in volume and pitch. The Doctor seemed completely immune to it. He smiled blithely as he looked at the viewscreen.

The voord didn’t have ears. But they put their hands to their heads as if they were in pain and one by one they collapsed. The Doctor turned off the feedback and reached for the door control. He bounded outside. Polly followed more slowly to see him bending over the unconscious Voord.

“That’s strange,” he said. “Do you see?”

“See what?”

“There are two types of Voord here. Look... these are the sort I’ve seen before. They have these transmitter-receivers on their heads. It’s what allows them to communicate telepathically. But only three of these have them. The others... they just have those horn-like protruberances.”

“But isn’t this some kind of suit?” Polly asked. “Like a wet suit.... rubber...” She touched one of the Voord and was surprised. “It isn’t... is it... it’s a sort of... skin...”

“It’s an exo-skin grown as a natural protection against the elements. That’s another unusual feature of the Voord. They grow their own ‘clothes’ essentially.” He shook his head. “I once found one that had been damaged. Acid got into the exo-skin and ate away the body within. All that remained was the skin... it did look rather like a wet suit. Except it wasn’t... terrible way to die. Even for something as ruthless as a Voord.”

He stood up and stepped over the bodies. Polly followed him. She wasn’t sure if she would be any use to The Doctor, but she was no use at all left inside the TARDIS.

“Have you got your little shorthand pad on you?” The Doctor asked when they stepped out into the corridor. Polly reached in her pocket and produced the pad and pencil. “Copy down that schematic.” He pointed to a map etched onto a metal plate fixed to the wall. Polly made a quick copy of it, writing the details down in shorthand.

“I suspect our friends could be in the processing room,” The Doctor said when she was done. “Which way?”

“Left, then straight on, then right,” Polly answered looking at her map. “Processing room? I don’t like the sound of that. Especially if Ben and Marton and the other men are there.”

“Nor do I,” The Doctor answered. “Nor do I. That’s why we’ve got to get there. Before something terrible happens.”

They turned left. Polly gave a startled gasp as they narrowly avoided tripping over another unconscious Voord.

“As I hoped,” The Doctor said with a note of triumph. That’s the snag with joined minds like the Voord have. If you send an augmented telepathic loop reverberating through a few of them it transmits to all the others. If we’re really, really lucky, they’re all like that. We’ll have no trouble reaching the processing room.”

So it proved. Every single Voord they encountered was out cold.

“Are they really evil?” Polly asked. “I mean... I know they kidnap people... but maybe they just feel the Cranns are in their territory or something. They look a bit pathetic all crumpled up like that, and I couldn’t help feeling a bit sorry for them. But...”

“The true Voord is a pitiless creature that cares for nothing but dominance over others, and is capable of dealing cold death to the innocent,” The Doctor replied. “But I wonder... that’s why I need to see this processing room...”

They reached the room. It wasn’t locked. It was meant to be guarded, but the Voord guards had collapsed. Inside there were three more of them lying on the floor.

Around the room were tables to which the kidnapped men, fifteen in all, including Ben were fixed. Most of them were conscious. Polly ran to Ben and began to unfasten the restraints that held him.

“Where’s Marton?” she asked. “I don’t see him.”

“That’s him. Over there. He was the first to be processed. The one next to him is partly done.”

Polly gasped as she looked at the two men Ben had indicated. One of them looked like a Voord with a black exo-skin. The other was part Voord, part Crann, still. The exo-skin covered one half of his body, including his neck and face and part of his scalp. He was unconscious, but his face was twisted in pain.

“That’s what they do with the men they take?” Polly asked, horrified beyond belief. “They make them into... into more Voord.”

“That’s what I suspected,” The Doctor said as he examined the two and the strange equipment used to do such a terrible thing to them. “Oh dear, oh dear, this is bad. Very bad.”

“Poor Marissa... That means... her brother was very probably one of the Voord who came to kidnap Marton. How awful.”

“Yes, I’m afraid that’s very possible,” The Doctor answered. “This isn’t so much an underwater city as an underwater space ship. I think it crashed here long ago and the Voord were forced to make the best of it without communications or means to escape. But they were only a few. So they used their technology to manipulate the DNA of their captives and create new Voord. This... this machine here... it boosts the intelligence... but suppresses the memory. They must be ever so slightly schizophrenic. And for some reason the new Voord don’t have the full antennae. It’s possible their telepathy is less acute.”

“But... Doctor... Oh, they’d be better off dead... can’t you... somehow...”

“Good gracious, no!” The Doctor responded. “The very idea. Polly, how could a gentle soul like you think of such a thing?”

“Because that’s such a horrible, dreadful kind of life... they can’t...”

“But, my dear, have you never heard the expression ‘where there’s life, there’s hope’?”

The Doctor turned and looked around. Ben had finished releasing the other men.

“Polly has a map. Take them all back to the TARDIS. They’ll be safe there even if some of the Voord start to come around. Polly, dear, you can help me.”

“Help you do what?” she asked.

“These two, at least, have only just been changed. Their DNA will still be pliable. It might be possible. It’s worth a try. Hold down those two levers there while I cross-switch the bio-electric feed and...”

He stood back as an eerie electric light beamed down upon the two men. At first, nothing seemed to happen. Then Polly gasped as she saw the black exo-skin begin to melt away from Marton’s face. It happened terribly slowly and was obviously painful to him. He screamed even though he was unconscious. So did the other man. Polly covered her ears and closed her eyes. It was dreadful to look at and to hear.

Finally, though, the men were silent. She opened her eyes and stepped close to Marton. She put her hand on his cheek. His skin, beneath the blue tattoos, was red as if he was terribly sunburnt, but he was whole. And he looked like himself.

He stirred and grasped her hand.

“Marissa?” he murmured.

“No, I’m sorry,” Polly answered. “But she’s all right. We’ll get you back to her, soon. Don’t you worry. You’re going to be all right.”

Marton opened his eyes and sat up on the table. He looked around to where The Doctor was reviving the other man.

“Doctor,” he said. “My thanks to you. For my life and my sanity.”

The Doctor was surprised. It was Marton’s voice, but his grammar and language pattern was quite different.

“They enhanced my intelligence,” he said. “I understand so very much more than I did before. Doctor... I understand what happened to me... and what you did to reverse it. And... the others....” He looked at the Voord lying on the floor, still. Doctor... I think we can save them... at least part of them... it may be too long since their bodies were changed... but we can save their minds...”

The Doctor looked at Marton and silently nodded. He and the other man, who Marton called Simmen, lifted one of the Voord without an antenna onto the table. They carefully repeated the process that had saved Marton and Simmen. The Voord writhed and strained against the restraints as something strange began to happen.

The exo-skin didn’t melt away this time. But the blank, eyeless, face began to take on real features. The eyes were completely black, without any whites at all, and the skin looked like rubber. But it was a face, and when the mouth opened a Human-sounding cry came from it.

“Mallik!” Marton leaned over the half-Voord, half Crann and put his hand on his black-skinned forehead. “Mallik, it is you... my brother-in-law.”

“M....Ma...Marton....” Mallik managed to say his name. “Marton... what has happened... what am I...” He lifted his hands and saw the black exo-skin and he cried out in grief. He understood the terrible truth. He could never be the man he used to be again. He could never be one of the Crann people.

“You are a new species entirely,” The Doctor said to him. “You have the Voord intellect and the Crann compassion. It will be hard, but the future has hope, at least. Will you help us to recover more of your fellows?”

Mallik nodded. He slid off the table and helped to lift two more of the converted Voord into place. It was painful for them, but Polly didn’t shut her eyes this time. She at least knew that there was hope at the end of the pain, now. She understood what The Doctor and Marton were doing.

Several hours later, all of the Voord who didn’t have antenna had been turned back to half-Crann. They were angry and upset, grief-stricken to find themselves in that strange condition. But they listened to The Doctor and Marton when they explained.

“This underground place is your home for now,” The Doctor said. “But it needn’t be a prison. You have the lift up to the surface. You have boats. You can visit the crannogs, visit your relatives. We will explain to them what happened to you, prepare them for what will be a shock, of course. But you can be reunited with your loved ones. You can find a way of living, two species side by side.”

“What about those?” One of the half-Voord pointed to the group of full Voord with their antenna in the middle of their heads. They had been rounded up and put in restraints. They sat, silent and sullen.

“They will be our prisoners,” Marton said. “They will be treated well. There will be no retribution, no cruelty. We are better than that. But they will remain prisoners. They will not be allowed to hurt anyone, ever again.”

There were a few whose anger and resentment went deep. They murmured about that idea. But the general consensus was with Marton. He nodded. All seemed to be as well as they could expect.

“I am returning to tell our people what has happened,” he said. “I will come back when they are ready for you to visit.”

“Give my sister all my love,” Mallik said to him. Marton promised he would. Then he returned with The Doctor and Polly to the TARDIS. The other men were relieved and glad to see their leader alive and well. They listened to his explanation of what had happened and what he hoped would happen in the future as The Doctor piloted the TARDIS back to the crannog.

“It won’t be easy,” The Doctor said to Ben and Polly as they stood and looked down at the fish swimming in the lagoon between the spokes of the crannog wheel. “Accepting that the men they knew are so very changed will be difficult for them. But they will manage. They will adapt. I think, eventually, the half-men will be integrated into the communities again. Their families will learn to look past their physical appearances to the men they love within. The underground place will just be a prison for the Voord for as long as they live. And after they’re gone... it will be forgotten. In time, these fences can be lowered. The crannog dwellers will be able to look out over their ocean in peace. They’ll be all right.”

“We did some good here, then, Doctor?” Ben said.

“Oh, indeed, we did,” The Doctor replied. “A lot of good.”