He tried to think of other plans he had used in the past to catch rings of thieves, but since the accident that had taken his memory he had worked largely on murder cases. Petty thieving belonged to a past before that-in the early years, when he and Runcorn had worked together, he thought wryly, not against each other. He had had flashes of going into the rookeries, those vast slums, which were part underground tunnels, part sagging tenements. There were passages, trapdoors, sudden drops, and blind ends-a hundred ways to get caught, and to get your throat cut. Your corpse would possibly go out on the tide, or if it finished in the sewer, most of it would be eaten by rats.

That world was violent and ugly. The poverty in it was so absolute that only the strongest and the luckiest survived. Police seldom went there at all, but if they did, they took with them someone they trusted not only in loyalty but in skill, speed, and nerve as well, and above all courage. He and Runcorn had trusted each other like that once.

In the rotting tenements of the waterlogged patch on the south bank known as Jacob's Island, there could be a hundred men hidden in the wrecks of buildings sinking slowly into the mud. The same was true of the teeming slums of the docks, the ever-shifting tides of the Pool of London with its great ships, its cargoes here one day and gone the next. The opium dens of Limehouse or the wrecks on the long stretches towards the sea might conceal anything. He would need to trust Orme with his life, as Orme would have to trust him. It would not come quickly or without testing.

"I'll work on a plan," he said aloud at last. "If you've got one, tell me."

"Yes, sir. I was thinkin'..." Orme stopped.

"Go on," Monk prompted.

"I'd like to catch the Fat Man," Orme said thoughtfully. "Owe 'im a lot, that one, over the years."

"I assume you mean a lot of harm, not a lot of good?"

"Oh, yes, sir, a lot o' harm indeed." There was an edge of emotion in Orme's voice that was extraordinarily sharp, as if from an accumulation of pain.

Monk was overwhelmed by how much he did not know about these men. Orme seemed not to resent him. In fact, he had deliberately steered him away from the station just now so that Farnham would not see him come in late. He had covered for him yesterday so that he could pursue the Havilland case.