He's dressed in a cap and Guernsey shirt;

They've got him a nurse and he sits on her knee,

And she calls him her Tommy

Bevy

Descent

Muster

Murder

Obstinacy

Pod

Serge

Smack

He waited while Masters relayed the list to the others.

'The poem feels like it's a word short in the last line.' Maggie rechecked the words she had copied into her notebook. 'It doesn't scan properly.'

'For God's sake, that's hardly important, is it?' complained Purbrick.

'Perhaps you're meant to supply the missing word,' she replied indignantly. 'Perhaps that's the whole point.'

'What does it need in order to scan? I mean, how many syllables?'

Maggie bounced her fingers over the page. 'Dum-dah-dah. Three.'

'Chimpanzee,' said Harold Masters, rising and going to the bookcase behind his chair. 'Chim-Pan-Zee. Decimus Burton. I mean, I'm guessing but it seems the most likely answer.'

'Forgive us, Harold,' said Maggie, with more than a trace of sarcasm, 'we're not all as well-read as you. Explain please.'

'Decimus Burton planned out the Zoological Society of London, as it was then known in 1826. London Zoo, as it's now called. There's a book here somewhere.'

'Conservation In Action?'

'That's the one.'

'To your left, up one shelf.'

Masters pulled down the photographic volume and opened it at the first chapter.

'Tommy the chimpanzee arrived in 1835,' he explained. 'A wonderful novelty in those days. Someone called Theodore Hook was moved to write a poem about him.'

'Vincent's poem?'

'I can't imagine there are any others. During the war the keepers packed off most of the animals to stop them from getting shell-shocked, but they ate the contents of the aquarium. This is interesting; someone cut a foot off Alice the elephant's trunk one bank holiday in 1870. Why would anyone do that?'

'More to the point, why would Sebastian send Vince to London Zoo?' asked Maggie. 'Nobody lives there. He doesn't need to have him appear before surveillance cameras at the monkey house, surely.'

'You're forgetting one thing. The only way to get to the zoo is by passing some of the most politically sensitive homes in the whole of London, the grace and favour properties of Regent's Park.'

They called Vince. Within another three minutes he was on his way north, precisely on time and exactly as Sebastian had planned from the start.

VINCE CRUNCHED two more uppers between his teeth and sat back in the cab, listening to the rain beating on the roof. He tried to force the puzzle through his tired brain. If what Masters had just told him about Sebastian and the creation of evidence from the surveillance cameras was true, what was the point of traipsing onwards to the zoo at all? His role in the game was almost finished. It only remained to be photographed in the last position and captured by the police, so that he could be blamed for whatever atrocity Sebastian had planned for his father's convention.

So why bother fitting in with Sebastian's plans? Wasn't he safer heading home right now? Except, of course, the League would have considered such an eventuality. It would not be safe to return to his flat. He had no doubt that if the police didn't get him, Sebastian's more violent acquaintances would be standing by to finish the job.

The cab sloshed across the pitted tarmac at Euston Tower and ploughed on through the storm up to Camden Town. It reached the park and entered the first of the gates into Outer Circle. Here the government departments were hidden behind trompe l'oeil mock-Grecian temples, painted a glaring white and set back from the road. Bedecked with posturing statues, they reminded Vince of over-iced wedding cakes, the apotheosis of good taste to some, the ultimate in kitsch to others.

Smearing a path through the steamed-over window with the back of his hand, he could make out the parade of security cameras mounted on grey steel poles. The curving park road bristled with them. Masters's theory had to be wrong; how could they record him speeding past through the condensation of a cabbie's window? Perhaps Sebastian had not allowed for the vagaries of the climate.

No. He would have thought of everything. Technology had ways of enhancing recorded images. He thought back over the night's challenges, trying to understand.

It was then that he remembered that this was the ninth challenge, and the final one was to follow. He ran through each of the journeys he had made and came to the same result. The League's letter had specifically stated that the challenge started at Victoria, which made the Savoy the first.

All of which meant that Vince was being sent north on a wild goose chase. He tried to remember how Sebastian's mind worked. He checked his watch: 6:13 a.m. He felt sure now that this was a ploy to keep him out of the way until the appointed hour, so that he would arrive in the final destination at exactly the right time. Sebastian would want him placed at the scene of the crime, just to make sure. It was the most incriminating piece of evidence he could manufacture, short of putting a smoking gun in his hand. And it was a way of maintaining the balance of the game, to fairly provide each member of the League with a chance to test him.

Ten members, ten challenges.

One envelope still to find.

But where was he supposed to start looking? Inside the monkey house of London Zoo?

Xavier Stevens stood in the rain outside Sebastian's Chelsea headquarters, looking up at the dimly-lit first-floor windows. He was in a deepening black rage. Not only had he been forced to perform all the dirty work as usual, but Sebastian had refused to authorise additional payment for the extra risks he had taken. He actually had the nerve to complain about the way the last task was handled. Why had the bodies not been taken to the river as he had requested? Where were they, in fact? Did he even think to bring back proof that they had been disposed of? Sebastian conveniently glossed over the fact that he had given Stevens carte blanche to remove any obstacles in his path, and that this had resulted in as many as six probable deaths.

It was obvious that the leader of the League of Prometheus resented his ability to achieve results, and that the others had only agreed to allow Stevens's induction into the group because he was prepared to carry out the kind of actions they were too cowardly to handle themselves. That was fine; he had not expected to be liked. He was quite prepared to settle for fear and respect. But Sebastian repeatedly made him appear a fool, and was happy to humiliate him in front of others over what, for him, was a relatively trifling sum of money. He had been sent packing without full payment, and was now determined to have the final say.

Stevens had overheard enough to understand what they were planning, and realised that the best way to hurt Sebastian was to upset the outcome of his scheme. He knew that the events of the night hinged on the League's scapegoat being set in place, because Sebastian had reluctantly told him why he needed Vincent photographed alone.

If the scapegoat was permanently removed from the game, the police would have to search out a new suspect. Stevens had an apposite suspect in mind. He checked his watch. If he was still hitting the schedule, Reynolds would be on his way to London Zoo by now. Let them find his body there with Sebastian's name attached to it, he thought bitterly. Let's see just how brave and powerful the League could be then.

Stevens hoisted a black leather pack on his shoulders, climbed back on his motorcycle and headed north.