As the soldier St John once brought another barrel back from Constantinople, I thought. 'What happened to it?'

'Captain Fenchurch paid us off in London. With the costs of the voyage he'd made little profit even with the furs, and he'd no plans then for another. So I went back to the colliers. But he gave me a bottle of the Polish stuff as a keepsake and I brought it here. Remember that night, Robin?'

'I'll not forget it in a hurry.' One of the others, a young fair-haired fellow, took up the tale. 'Hal came in and told us all about the Poles, their long beards and pointy fur hats and the dark forests, then he brought out this bottle of pale stuff and passed it round, saying it was what the Poles drank. You warned us it was strong stuff though, Hal, told us only to take a sip.'

'You knew better, though, Robin,' one of the others said, laughing.

'I thought I did,' the fair-haired fellow replied. 'I took a long swig at the bottle and, by Our Lady, I thought my head was going to burst. I spat the stuff straight out, right across the table. It was winter and dark, there were candles on all the tables. The stuff hit the candle and knocked it over and then – by Jesu-'

'What?'

'The whole table caught light. The stuff should have put the candle out, but the whole top of the table burst into a strange blue flame. You can imagine the effect it had. Everyone jumped up – all over the tavern people were shouting out and crossing themselves. Then the fire died as quickly as it started, leaving hardly a mark on the table. It was this very one.' He laid a hand on the scuffed table-top, which was indeed unmarked.

'It was like witchcraft,' Hal Miller said. 'After that I threw the stuff away.'

I frowned. 'You said this was in the winter.'

'Ay, January. I remember we weren't looking forward to the long voyage up the coast in the storms.'

'When did the man Toky approach you?'

Miller's eyes were watchful again. 'Later that month, when we got back from Newcastle. The story had got around, see, about a foreign drink that could catch fire. He came here one night with another, a big man. Strutted in as though he owned the place and came right up to us. His big mate was carrying an axe – half the tavern emptied at the sight of it. He said he'd been asked to get some of this stuff, said his master would pay.'

'Did he say who his master was?'

'No, and we didn't ask. He said he'd pay good money, though. He didn't believe me at first when I said I'd chucked the bottle off Queenhithe dock. Started to get threatening, but he went away when I gave him Captain Fenchurch's address. I was sorry I did, but I was afraid. I enquired after Fenchurch later, from one of his servants. Fenchurch had told the servant he'd managed to sell the barrel on and made a handsome profit.'

'Who to?'

'The servant knew no more. The pock-faced man, I assumed.'

'Marchamount? Bealknap? Bryanston? Do any of those names ring any bells with you?' I did not add Rich or Norfolk's names, for everyone in London knew those.

'No, sir, I'm sorry.'

'Where does Captain Fenchurch live?'

'On the Bishopsgate Road, but he's abroad again. He's taken a ship to Sweden. He asked me to join him, but I've had enough of these devilish places. He won't be back till the autumn.'

Then at least he had not been killed too. 'Thank you, anyway.' I nodded to Barak, who took out his purse and passed some coins to Miller. 'If you think of anything more,' he said, 'you can reach me by way of the landlord.'

I led the way outside, halting a little way from the inn. The Vintry crane stood outlined against the starlit sky like the neck of a huge swan. I looked out over the dark river.

'Stumped again,' Barak said. 'If only that arsehole captain hadn't gone abroad.'

I raised a hand. 'Think of the dates, Barak,' I said excitedly. 'Master Miller causes a great stir in the tavern in January. That's three months after the Greek Fire was found at Barry's, but two months before the Gristwoods contacted Bealknap as the first step in getting to Cromwell. What were they doing in those months?'

'Building and testing the apparatus?'

'Yes.'

'And trying to produce more Greek Fire, using the formula? The Polish stuff must be part of it.' Barak looked excited.

'Or perhaps they heard the story of the fiery liquid, and sent Toky down here to try and get some to see if it could be of use.'

'But they must have known what they needed and what materials. They had the formula.'

'You'd think so, wouldn't you? So Toky's paymaster, whoever it was, was involved at a very early stage. Working with the Gristwoods. Months before the approach to Cromwell.'

'That doesn't make sense. If he was working with the Gristwoods, why have Toky kill them?' He stared at me. 'Perhaps the Gristwoods went to Cromwell behind their first sponsor's back, perhaps they were looking for a better offer.'

'Then why wait until two months after the approach to Cromwell to kill them? And if the person behind the killings is one of our suspects, the Gristwoods wouldn't use any of them as an intermediary to Cromwell.' I raised my eyebrows. 'I must talk to Bealknap, Barak. We need to lay hold of him.'

He gave me a serious look. 'What if Toky's got to him already? Shit, they got to the founder just before we did – what if Bealknap's dead too?'

'I'd rather not think of that. Come on, we can check at Lincoln's Inn before we go home.' I cast a glance back at the gloomy tavern. It was a strange place. It struck me that it was only at night that London showed its true, sinister face.

At Lincoln's Inn there was only a note from Godfrey to say Bealknap had not returned. His door was padlocked and next morning, when I went in again, it was still locked. His locks and the guards at the gatehouse protected his chest of gold, but of Bealknap himself there was still no sign. And six days left now.

Chapter Thirty

IT WAS TURNING INTO a frustrating morning. After going to Lincoln's Inn to find no trace of Bealknap again, I had ridden over to Guy's, but my note was still on his door. Why could people not stay in one place, I thought as I rode to my next port of call, the house where Cromwell had sent the Gristwoods and Kytchyn, to keep them out of sight.

The house was in a poor street near the river, with flaking paint on the doors and shutters, which were closed despite the heat of the morning. I tied up Genesis and knocked at the door. A large man in a dun-coloured smock opened it. He stood in the doorway, eyeing me suspiciously.

'Yes?'

'My name is Matthew Shardlake. I had the address from Lord Cromwell.'

He relaxed. 'Ay, sir, I had word you would be coming. Come in.'

'How are our guests?'

He made a grimace. 'The old monk's not too bad, but that woman's a termagant and her son's crazy to get out. Any idea how long they're to be kept here?'

'It shouldn't be more than a few days.'

A door opened and Goodwife Gristwood emerged. 'Who is it, Carney?' she asked nervously. She looked relieved when she saw it was only me. 'Master lawyer.'

'Ay. How are you, madam?'

'Well enough. You can go, Carney,' she said in a peremptory tone. The big man made a face and walked away. 'He's an impertinent fellow,' Madam Gristwood said. 'Come into our parlour, sir.'

She led me into a hot shuttered room, where her son sat at a table. He stood when I entered. 'Good day, sir. Have you come to tell us we may go? I want to be back at my work-'

'I am afraid there is still danger, Master Harper. A few days more.'

'It's for our safety, David,' his mother said reprovingly. Goodwife Gristwood had got over her shock, it appeared, and recovered her natural character as one who would rule any roost she landed in if she could. I smiled.