I nodded and he produced his little metal tool and bent to pick the lock as he had at the Wentworths' well. I looked uneasily across the dock at the men unloading the boat, but they paid us no attention.

'I hope the bastards haven't gone,' he muttered. 'They might move the stuff regularly to avoid being found.'

'There may only be Toky left.' Even alone, I thought, he would be a dangerous adversary.

There was a click and the padlock fell open. 'There!' Barak said. 'Let's see what's inside.'

The door opened smoothly on well-greased hinges. Barak shoved it back against the wall lest anyone was concealed there. It made a hollow, echoing bang. A dark interior was revealed, lit only by one glassed window high up. The warehouse was as wide as the nave of a church and, I saw, quite empty. There was a musty smell of cloth and the stone floor was Uttered with tiny pieces of wool fibre. Drawing his sword, Barak stepped in. I followed.

'Empty as an old nun's womb,' he said.

I looked up at the end of the warehouse. A flight of wooden steps led up to an upper floor, which was merely a wooden platform running round the wall except for a room next to the stairs, its door closed.

'That must be the office,' I said.

'Shall we go up?'

I nodded, my heart beating fast. We climbed the rickety wooden staircase carefully. I looked at the door, afraid that it might open and that Toky might fly out at us. Barak held his drawn sword in front of him and I clutched the dagger at my belt. But we reached the platform safely. I saw that the door to the office was also secured by a padlock. It seemed darker now; glancing up at the high window, I saw the sky was dark as a winter dusk. I heard a faint rumble of thunder.

Barak bent to the padlock. I coughed at the fibre dust our feet had stirred up. The place looked as though it had not been used for months. I cast my eye along the platform. There was a bale of cloth in one corner. Barak grunted with satisfaction; he had the padlock off. He stepped back and kicked the door open.

The room was empty, there was nothing at all in there, just the big open hatchway giving a view of the lowering sky, the end of the winch secured to the floor with bolts. Then I saw a door to a second room. I nudged Barak and he threw it open, then whistled at what was inside.

A table stood in the middle of the room. There was a beer jug and three plates, an unlit tallow candle and a hunk of bread. Another bale of cloth by the table served as a seat. We stepped inside.

'Someone's been here very recently,' I said.

Then Barak stopped as he saw what was stacked against the far wall. A long metal pipe with a wick at one end, a complicated-looking pumping machine, and a metal tripod, all bundled together beside a large metal tank.

'The Greek Fire apparatus,' he breathed. 'And look at this.'

I saw, beside the ugly tangle of metal, a tall, narrow porcelain vase about two feet high. It was the type that might be used to plant a bush for display in a courtyard. I had seen ones like it at the House of Glass. I approached and, very carefully, lifted the little lid. Inside I saw a dark viscous liquid. The familiar vile stench of Greek Fire set the hairs at the back of my neck prickling.

I felt Barak's hot breath on my cheek as he stood beside me, peering into the vase. He dipped a finger into the stuff and lifted it to his nose. 'We've got it,' he breathed. 'God's blood, we've got it!' He stepped back, his face alight, gripping his sword handle hard in his excitement.

'It's probably all they have left,' I said. 'It would barely cover the bottom of that tank. Nowhere near enough to burn a ship.'

'I know.' Barak sniffed his finger, held it from him and sniffed again, as though the dreadful stuff were some wonderful perfume. 'But there's enough to show the king, enough for him to give to his alchemists. This could save the earl-'

There was a laugh behind us, loud and triumphant. We froze, then turned slowly. Toky stood there, a broad grin on his ravaged face. Two others were with him, a short stocky fellow with a straggly beard and a younger man, less rough-looking than the others. Him I had seen somewhere before. All three had swords raised.

'Drop the weapon, baldy,' Toky said in his sharp voice. 'You're outnumbered.' Barak hesitated a moment, then let his sword fall to the floor with a clatter.

Toky grinned again. 'Well, my beauties, we've been waiting for you. By God, you're hard to kill, but we've got you now.' He nodded at his younger confederate. 'Master Jackson here saw you drinking beer in Potter's Lane and hurried back to warn us. We padlocked the door so you wouldn't think we were here, hid round the corner, then came back once you'd broken in.' The bright catlike eyes fairly danced with delight. 'We thought you'd come up here and we guessed what you'd be looking for. You were so intent on the Dark Fire you never heard us creep across the boards.'

'Dark Fire,' I repeated. 'So you know that old name.'

'Ay, it's a better one than Greek Fire, for this is English Fire now and it will bring a mighty darkness to our enemies. And gold to us.' His smile broadened. I wondered if he knew Wright was dead – Barak said they had worked together for years. Perhaps he did not care. He laughed, an eager breathy laugh, then nodded at his confederates. 'Cadit quaestio. The discussion is over. See, I know some lawyers' Latin.'

'So I heard. When you were a novice.'

'You know that, eh? Ay. Before they threw me out for charging the monks to grope me. I was pretty once.' He smiled. 'Kill them both,' he said.

Barak set his jaw. I stepped back, pointing to the jar. 'This is all you have left, isn't it?' I said hurriedly, talking for my life. 'You don't know how to make more – you failed. The barrel from Barty's was nearly used up in the demonstrations. It was all a trick to disgrace Cromwell. We know that and so does the earl.'

Toky's eyes narrowed. 'Then why are you here? Why not a troop of soldiers?'

'It was only a guess brought us. We didn't know where the stuff was. But others will follow soon, you'd do best to turn yourself over to the earl's mercy now.'

'Oh, shit,' the bearded man said, but Toky silenced him with a glare. Toky was frowning now, his ebullience gone. He ran a hand over his pockmarked face, eyes glittering between me and Barak.

'Do you know who our masters are?' he asked.

'Yes; they will be under arrest soon.' So there was more than one.

'Name them,' Toky snapped.

I hesitated. 'Richard Rich,' I said.

Toky smiled slowly. 'Rich, My arse. You don't know – this is bluff.'

'Kill them,' young Jackson said nervously. 'Get them out of the way while there's still time.'

'Not yet, don't be a fool,' Toky rasped. 'Our masters will need to hear how much they know. Fetch them here, they will have to decide what's to be done.'

'Both?' The young man's accent had some effort at cultivation; the accent of someone who served a rich master. Where had I seen him before?

'Ay. Tie them up first.' He nodded at some coils of rope in the corner. 'Use what we tied the founder with.'

Our hands were grasped roughly and pinned behind us. I felt a damp, greasy rope passed round them. We were manhandled into a corner and shoved down roughly onto the boards.

'Hurry, Jackson,' Toky urged.

With a last worried look at us, the young man left the room. I heard his footsteps descending the stairs. Toky sat on the bale of cloth, looking at us thoughtfully. The bearded fellow sat on the table, bit off a hunk of bread and washed it down with a swig of beer. He smiled at us, yellow teeth like a rat's dimly visible in the gloom.

'You're a scarecrow-looking pair to have caused so much trouble. Ain't they, Toky?'

Toky grunted; his ebullience had evaporated.