Holmes, despite thinking that he should have gone to bed, hadn't. Instead, he'd managed to fall asleep while writing an entry in his log about the incident. He quickly awoke when the electric door to his room noisily slid open.

Holmes coughed. "Um, Edward."

"Sir," the young man said, "three Niagorn have been found attacking the door to the dome."

"What?" Holmes became suddenly alert. "I thought they were non-hostile!"

"So did we all, sir."

"Is everyone safe?"

"Oh yes, sir," Edward nodded, "everyone's fine. The Niagorn only attacked with their claws."

"Well, they are only beasts," Holmes nodded in satisfaction. "Where are they now?"

"Science wing," Edward replied. "Sedated. When Miss Castle comes back, she can look over them. However..."

"However what?"

"Well, one of the beasts was carrying a wad of bark. Strange symbols were etched into them," Edward babbled.

"Any idea what they mean?" Holmes asked.

"Oh, no sir. When the scientists come back..."

Holmes felt a pang as he remembered his missing daughter for what seemed like the fortieth time that day.

"Yes, Edward," Holmes nodded. "You can go now."

"Look at these hieroglyphics, Leela."

Leela peered at the strange symbols and frowned. "Do you know what they mean?" she asked.

"Not the foggiest – but they look nice."

"There is no reason to look at them if you do not know what they mean," Leela announced. "We must move on. You promised."

Three purple Niagorn lay, still and silent, in an empty laboratory. They had been sedated. With no qualified scientists around to feed them or survey them, they just had to be kept sedated until one of them woke up – or was rescued.

A guard kept watch over them. He was hovering hesitantly in the corner when he saw one of the beasts move. It shook its head from side to side, and started to sit up.

"'Ere," the guard called. "Don't you wake up on me – I can't sedate you again!"

The Niagorn ignored the man's protest, hissing indeterminably before thundering off the large trolley onto the floor.

"No!" the guard yelled. "Go back to sleep!"

The Niagorn glanced around the room before its eyes fell on its two companions, both as still and silent as before. It turned its massive head towards the guard and bellowed.

"Go away!" cried the miserable guard. "I don't want to be eaten!"

The Niagorn had no intention of eating the guard, but it nevertheless got shot by the guard's stun gun before long. Its fall made several beakers shatter on the floor.

"Um..." the guard looked back into the corridor, yelling, "I could use some help here!"

The Doctor and Leela entered a huge underground chamber. It was decorated similarly to the passages, covered in the same small symbols. Even the ceiling – metres above anyone's head – was decorated intricately.

However, the first thing either traveller noticed about the underground chamber was that it had a large alien creature sitting in the middle of it.

"Uhm, hello," the Doctor waved. "Are you by any chance a Niagorn?"

The Niagorn's voice was almost snakelike: a low hiss, however words were clearly distinguishable. "How do you know our language?" it hissed. "No Earth man knows our language."

"Well, we do," the Doctor avoided the question. "Who are you?"

The Niagorn, in return, ignored the Doctor's question altogether. "You are not an Earth man," it decided. "Why are you here, alien?"

"I'm here on behalf of the human colony," the Doctor announced, grandly tossing one impossibly long stretch of scarf over his shoulder. "They have good reason to believe that you've kidnapped two younger colonists."

"Did you encounter our messengers?" the Niagorn hissed.

"Messengers?" the Doctor asked. "Can't say I did, no... what message were they delivering?"

"You are not an Earth man," the alien hissed. "It does not concern you."

"Now, look. I can't help you if you don't tell me what's wrong, can I?" the Doctor smiled.

"Earthmen make us sick," the Niagorn explained, hissing slowly. "Our numbers are depleting."

Leela felt it was about time she had a say in things. "Just because your tribe is dying does not mean you can kill the colonists. It is not fair."

"We did not kill them!" the Niagorn hissed angrily. "They are fine! They are perfectly safe! We are not monsters!"

"Where are they, then?" Leela asked. "If you know that they are safe, you must know where they are."

"We delivered a message to the Earthmen." The creature hissed very quickly now. "We will trade the Earthmen for peace."

"Don't you think that's a little excessive?" the Doctor enquired thoughtfully.

"No."

"Why wasn't asking very nicely an option?"

The Niagorn almost seemed to sigh. "Earthmen do not understand us."

"Forgive my ignorance," the Doctor persisted, "but if they don't understand you, how were your messengers supposed make contact, hm?"

"They carried written messages," the Niagorn's hiss almost sounded bored. "We thought the humans might understand them."

"Ahem," the Doctor cleared his throat. "If I might make a suggestion."

"If you desire to, alien."

"The colonists understand both Leela and I," the Doctor stated. "Maybe we could negotiate on your behalf."

"That is a good suggestion," the Niagorn decided after a little thought.

"Excellent," beamed the Doctor. "Come along, Leela."

"No," the Niagorn bellowed. "You will go alone, alien."

"What?" the Doctor asked. "That was not a condition!"

"It is our way," the Niagorn replied. "Good luck, alien."

"But –"

"Good bye."

Leela turned towards the Doctor. "I am a warrior," she reminded him. "I am able to take care of myself."

"That's what worries me," the Doctor said quietly. "Goodbye, then. I'll see you in... oh, an hour, I should think."

"Goodbye, Doctor."

And so the Doctor tumbled through the green forestry, in order to negotiate.

But first, he had to explain Leela's absence.

"What do you mean, the Niagorn kept her?" Holmes demanded furiously.

"It's not that hard, really," the Doctor pointed out.

"No, of course not," Holmes admitted. "The Niagorn are barbarians!"

"Must you be so narrow-minded?" the Doctor demanded. "They're not like you, you know – and it just so happens that whatever you're doing to them is making them quite ill!"

"That is no excuse," Holmes snapped. "They've overreacted quite enough."

"Overreacted? Their people, their way of life, it's dying, you understand. If humanity was dying out, wouldn't you do just the same? Wouldn't you overreact?"

"We would not descend to such levels," the leader announced confidently. "They've taken Olivia, Elissa... and now your companion. We don't know what they could do next."

"Well, it's definitely not –"

"We're organising an attack," Holmes decided. "If you'll leave, please."

"You're making a big mistake, you know," the Doctor pointed out. "What do you think the Niagorn'll do if they find you're planning an attack, eh?"

"Nothing," came the bitter response. "Now go, Doctor."

Leela, thrown into the same room as the two captured colonists, found herself the subject of two startled stares.

"Who are you?" Elissa demanded shrewdly.

"Never mind that," Olivia said immediately after. "Do you have any food?"

Leela paused before answering. "My name is Leela," she replied, "and I do not carry food."

"Aww," Olivia sighed. "I haven't eaten since yesterday."

"Who are you?" Leela directed her question to both girls.

"I'm Elissa," Elissa replied. "She's Olivia." There was a pause in conversation after that as no one quite knew what to say.

"Do you know the way out?" Olivia asked eventually.

"I do not."

Olivia groaned. "So... hungry..."

"Hullo, K9!"

The Doctor had decided that he should prevent the attack on the Niagorn, and to that end he went back to the TARDIS to collect his faithful robot dog.

"Greetings, Master," K9 replied typically.

"Now, listen, K9, you and I are going to head to a large dome, all right? While there, we – or you – will destroy their weapon collection! Or at least the vast majority of it."

"Affirmative," K9 replied. "Query: what is the dome?"

The Doctor sighed. "Well, when we get there I can show you."

"Affirmative."

The Doctor and K9 made their way, unchallenged, down the annoyingly white corridors.

"You would think," the Doctor had announced, "that colonies would think of more variety in their colour schemes. Such as orange. What do colonies have against the colour orange, K9?"

"Unable to answer, Master."

Eventually, through clever guesswork and the fact that it was advertised on various signs along the way, the Doctor and K9 got to the armoury.

"Now, K9," the Doctor said, "cut through that door, all right?"

"Affirmative."

"Yay! Food!" Olivia beamed as she noticed a tray of assorted plants that had been put there while she'd been banging her head against the wall complaining about it.

"What is it?" Leela asked curiously, staring at the green and white leaves and wondering how they constituted food.

"They're a native plant," Elissa explained matter-of-factly. "Though we had no idea... this must be what the Niagorn eat!"

"And me," Olivia smiled.

"What? No, Olivia – you can't eat this!"

Olivia looked heartbroken. "Why not?"

"Firstly," Elissa stated bossily, "we don't know if it's safe to eat. Secondly, it could tell us all about the Niagorn."

"Why wasn't it studied already then?"

"It probably was," Elissa answered, "but I don't know the findings of every plant on this planet, you know."

Olivia was crestfallen. "So... even though it's food... I can't eat it?"

"No."

"Hey, what are you doing?"

The Doctor tried to gesture to K9 to stop blasting the door, but K9 evidently wasn't looking.

The young woman who'd noticed the Doctor walked closer, and looked from the metal door with a hole in it to the metal dog.

"Your dog's blasting the door in!"

"Um... well..."

"Affirmative," K9 chirped.

"You can't do that!" she complained.

"But I have to prevent the attack on the Niagorn!"

The young woman stared incredulously at the Time Lord before half turning away and shouting, "GUARDS!"