‘No, I did not. But I’ve as good as found one. And the truth is, I don’t know what to do with her.’ The fat man growled some more like a sulky bear. ‘Anyhow, what about you?’

‘What?’

‘Well, you got what you came for. Serving the emperor, hey?’

‘Mmm.’ The laughter dried in Erlan’s throat, his grin turned a little sour. ‘I suppose I did.’ He tried not to think how he had clung to that empty hope. Gods, what had he expected anyway? Only a fool would rely on the word of a half-crazed holy man, but he had clung to it like a drowning man to timber. If he ever told Einar that he had crossed half the world on the strength of it. . . that they all had. And what had come of it? The twins were dead. And he was still under the Watcher’s curse.

He looked across the table at his friend. Even sour and irritable, Einar couldn’t suppress the humour dancing in his eyes. He was only ever a dry remark away from laughter. And yet Erlan feared for him, feared for all of them. Feared for Lilla most of all.

‘So you’re coming then,’ he said.

‘Aye. I’ll come. Maybe that crazy wench will learn to appreciate me while I’m gone. Just tell me what we have to do.’

Katāros wiped his dagger clean on the inside of his cloak. His lip curled at the irony of it. The evidence was gone in a moment. But one couldn’t wipe away the memory so easily, he thought. The stink of it lingered too.

Then again, the fire-maker’s innards were no worse than the usual stench in this quarter of the city, with its open gutters, liquid sewage running everywhere, midden heaps on street corners and puddles of vomit outside every tavern.

The long hours with Nikolaos had paid off. Eventually. But the lampros had been stubborn. Brave, even. Katāros had been forced to use all his powers of invention to coax the necessary information from him. But he was satisfied that he had extracted everything the man had to tell.

Materials, composition, conditions of preparation, quantities, proportions, viscosity. . . process, all was process. And that was merely to make the substance. The real trick, it became clear, was in the mechanics of the fire-syphon. Pump, nozzle, ignition temperature, pipework. But all the details were safely recorded now on the long scroll of parchment in the leather cylinder in his hand. Written in Greek and also in Arabic for good measure. Everything that Maslama and Abdal-Battal needed to tip the scales of providence in their favour.

‘I should be staying,’ said the Jewess, who had joined him halfway through the night’s grisly business. The work proved too much for her at times but she had swallowed her qualms and stayed the course. ‘My task here is still not complete.’