'That would seem logical.'

'So what we need to do is throw a spanner in the works,'

said the Doctor. He walked over to one of the gla.s.s cases and tapped his finger against its surface. 'Now, if we could modify the ammunition of this armour-piercing launcher . .

'Modify it in what way?' asked Zoe.

The Doctor rummaged around for the sh.e.l.ls. 'We want to change these bullets so that they impact into these creatures but do not explode. Instead we want them to give off a vast amount of heat. Any other Mecrim will therefore not recognize the creature as one of its own species but as a potential threat. If we can change the heat signature of some Mecrim to that of, say, a reasonably sized elephant, then we might be able to start a civil war.'

Zoe remembered that soon after she met the Doctor he had shown her a mind-projected account of his most recent encounter with the Daleks. One 'humanized' Dalek faction had been set against another. The slaughter was colossal.

'There is a flaw with this plan,' she said. 'There's almost certain to be at least one survivor. And even to get to that stage we will have to have fired at well over half of all Mecrim.'

'That's true,' said the Doctor. 'But we'll burn that last bridge when we've crossed it.' He opened a strong metal box and began to unpack its dart-like explosives. 'See if you can find out from the computer system how many creatures we're facing.'

Zoe nodded and began to tap at the keyboard. 'You'll need to ensure that the heat emission is consistent with a living creature,' she commented. 'The Mecrim eventually recognize flames and so on as non-living heat sources.'

The twins sidled over to the Doctor's side. 'Do you know what you're doing?' asked Raitak.

'Of course,' said the Doctor, jabbing a pin into the outer casing of one of the sh.e.l.ls. 'But one false move and this whole building will go up in smoke.'

'We'll keep very quiet,' said Reisaz, taking the hint.

There was a loud thump from the shutter, two figures now seeming to hurl themselves at the thick metal. Although designed to resist almost anything short of a thermonuclear explosion the Doctor did not believe that the metal would hold out much longer. It was buckling and a single claw had already worked through into the room.

'Also scan through the rest of the files involving the Mecrim,' said the Doctor. 'Tell me anything that refers to the demise of this miniature civilization, or any other flaw in the Mecrim that we can exploit.'

'There were twenty-seven of the creatures originally,' said Zoe, having found the information she was looking for. 'I just hope they haven't bred over the past few centuries.'

The Doctor stared at the shutter. Most of an arm had now been forced through, the claws thrashing against the metal.

'So do I,' he said.

Confidential Memorandum

From: Dr J. Alforge, Dr J. Alforge, To: C. Y. Dugied, C. Y. Dugied, Pr. Mecrim Control 429 Date: 2416,2111,21:55 2416,2111,21:55 (WST).

Subject: Mecrim claw

Dear Ciaran

The report you requested is attached. To summarize, the strength of the Mecrim claw does not depend entirely upon the composition of the talons or on the pressure exerted by the arm itself. You know I'm no physicist, but the gist of it seems to be that the Mecrim can vibrate the molecules of its claw to allow it to penetrate another substance. Imagine being able to turn your hand into a gaseous state - you could then 'merge' with some other object, and then 'reform'

your hand. The results, as we have already seen, are truly horrific. The Mecrim are able to 'push' their claws through humanoid tissue with the minimum of effort.

The lab tests on the single Mecrim trapped in a lead cell make terrifying reading.

Are you seeing Marcus tomorrow? Say hi for me.

Best wishes

Jenn

Confidential Memorandum

From: Dr J. Alforge, Dr J. Alforge, To: C. Y. Dugied, C. Y. Dugied, Pr. Mecrim Control 429 Date: 2417,3004,10:15 2417,3004,10:15 (WST).

Dear Ciaran

Another day, another letter, disguised as a memo. How the devil are you? I'm feeling awful, if truth be told. I've had a pain in the stomach all day - feels like it's more than just nerves.

The Head Observer from our mysterious benefactors was here today. He seemed very impressed by our reports. I think he's a s.a.d.i.s.tic b.a.s.t.a.r.d. For G.o.d's sake don't file this with the official memos.

Hope you're well anyway. Best wishes

Jenn

Confidential Memorandum

From: Dr J. Alforge, Dr J. Alforge, To: C. Y. Dugied, C. Y. Dugied, Pr. Mecrim Control 429 Date: 2417,0405,11:25 2417,0405,11:25 (WST).

Subject: Mecrim gut microbe 23D Mecrim gut microbe 23D

Dear Ciaran

Very bad news. The above-noted microbe, extracted for detailed research from Mecrim study number 09, has proved to be a highly dangerous one. Nik thinks that contact with air could prove deadly for humanoid life: I'm ordering thorough checks of our corpse disposal routine, and of our lab procedures. Nik's report will follow.

Please put some ships on stand-by in case we need to evacuate this place. I request that emergency science colony status 171 be granted until we are sure that this microbe hasn't hasn't escaped into the atmosphere. escaped into the atmosphere.

Get that b.a.s.t.a.r.d out of my hair. He should have gone days ago.

Still feeling ill. Let's hope it's not . . . No, let's not even think about it.

Cheers

Confidential Memorandum

From: Dr J. Alforge, Dr J. Alforge, To: C. Y. Dugied, C. Y. Dugied, Pr. Mecrim Control 429 Date: 2417,1106,19:50 2417,1106,19:50 (WST).

Subject: Mecrim gut microbe 23D Mecrim gut microbe 23D

Ciaran -