'I will help, my lord,' I said quietly.

He looked at me for a long moment, then gestured to Barak. 'Jack, the Bible. Before I tell you more, Matthew, I must have your oath to keep this matter secret.'

Barak laid a luxury edition of the new Great Bible, which had been ordered to be set in every church, upon the desk. I looked at the brightly coloured title page: King Henry on his throne, handing copies of God's Word to Cromwell on one side, Archbishop Cranmer on the other, who in turn passed them down to the people. I swallowed and touched the book.

'I swear I will keep the matter of Greek Fire privy,' Cromwell said. I repeated the words, feeling I was turning a key in a set of fetters that bound me to him again.

'And help me to the best of your ability.'

'To the best of my ability.'

Cromwell gave a satisfied nod, though he still sat hunched over his desk like some great beast at bay. He picked something up and turned it over in his big hands: it was the miniature portrait he had had at the Domus.

'The reformist cause is tottering, Matthew.' He spoke quietly. 'It's even worse than the rumours say. The king's afraid and grows more afraid every day as Norfolk and Bishop Gardiner tip their poison in his ear. Afraid of common people reading the Bible, fearing they'll end by overthrowing the social order in bloody chaos like the Anabaptists at Münster. Radical reformers stand in danger of the fire – you know Robert Barnes is under arrest?'

'I had heard.' I took a deep breath; I did not want to hear this.

'The Act of Six Articles the king forced through last year takes us halfway back to Rome and now he wants the lower classes forbidden from reading the Bible. And he's afraid of invasion.'

'Our defences-'

'Could never withstand a combined onslaught by France and Spain. King Francis and Emperor Charles have quarrelled and the threat's over for now, but things could change again.' He took the miniature and laid it on top of the Bible. 'Do you still paint, Matthew, for a pastime?'

I looked at him, puzzled by his change of tack. 'Not for some time, my lord.'

'Give me your opinion of this portrait.'

I studied it. The woman was young, with attractive if vacuous features. The image was so clear you could imagine you were looking through a window at her. From the jewels set in her elaborate hood and in the collar of her high-cut dress she was someone of wealth.

'This is beautiful,' I said. 'It could almost be by Holbein.'

'It is by Holbein. It is the Lady Anne of Cleves, now our queen. I kept it when the king threw it in my face.' He shook his head. 'I thought I could shore up our defences and our reformed faith at the same time by marrying the king to the daughter of a German duke.' He gave a short, bitter laugh. 'I spent two years after Queen Jane died trying to find a foreign princess for him. It wasn't easy. He has a certain reputation.'

He was interrupted by a gentle cough. Barak was looking at his master anxiously.

'Jack warns me I am going too far. But you've given your oath, haven't you, Matthew, to keep your mouth tight shut?' His hard brown eyes bored into mine as he emphasized the words.

'Yes, my lord.' I felt sweat forming on my brow.

'Eventually the Duke of Cleves agreed we could have one of his daughters. The king wanted to see the Lady Anne before agreeing to marry her, but the Germans took that as an affront. So I sent Master Holbein to make a picture. After all, his genius is to make exact representations, is it not?'

'No one in Europe does that better.' I hesitated. 'And yet-'

'Yet what is an exact representation, eh, Matthew? We all look different in different lights, can never be caught completely in one glance. I told Holbein to paint her in the best light. And he did. That was another mistake. Can you see?'

I thought a moment. 'It is full face-'

'Not till you see her in profile do you realize how long her nose is. Nor does it show her high body odour, nor how she didn't speak a word of English.' His shoulders slumped. 'When she landed at Rochester in January the king disliked her on sight. And now the Duke of Norfolk's dangled his niece before the king, schooled her to catch his fancy. Catherine Howard is pretty, not yet seventeen, and he's caught. He drools over her like an old dog over a fine joint of meat and blames me for saddling him with the Cleves mare. But if he marries Norfolk's niece, the Howards will have me dead and England back under Rome.'

'Then all that's happened these ten years,' I said slowly, 'all the suffering and death, it would have been for nothing.'

'Worse than nothing, there'll be a cull of reformers that would make Thomas More's inquisitions seem mild.' He clenched his big fists, then got up and walked over to the window, staring out over the lawn. 'I'm doing all I can to discredit them, find papist plots. I've had Lord Lisle arrested, and Bishop Sampson; he's in the Tower, I had him shown the rack. But I can find nothing – nothing.' He turned and faced me. 'Then I told the king about Greek Fire. He can't wait for the demonstration; he loves weapons of war, and warships above all. He sees us making England's navy the greatest on the seas, clearing the French from the south coast. He's my friend again.' Cromwell clenched his fists. 'A foreign power would pay much for that formula. I'm setting extra spies in the ambassadors' houses, all the ports are being watched. Matthew, I must have that formula back safe before the demonstration. Today is the twenty-ninth of May. We have only twelve full days.'

Then, to my surprise, I felt an alien emotion towards Thomas Cromwell: I felt sorry for him. But I reminded myself that a creature at bay is at its most dangerous.

He sat up, slipping the miniature into the pocket of his robe. 'Michael Gristwood had to use three intermediaries to get to me. They are the only others who know about Greek Fire. Two of them are lawyers, men of Lincoln's Inn that you know. The first was Stephen Bealknap-'

'Not Bealknap. Dear God, he's the last one any man should trust. And they'd had a falling out.'

'So I hear. They must have mended it.'

'I've a case on against Bealknap.'

Cromwell nodded. 'Will you win?'

'Ay, if there's any justice.'

He grunted. 'Talk to him, find if he told anyone else. I doubt he did, for I told Gristwood to order him from me to sew up his mouth.'

'Bealknap has a care for his safety. But he's a greedy rogue.'

'Find out.' He paused. 'When Gristwood told Bealknap about Greek Fire, he gave thought as to who might have access to me. He went to Gabriel Marchamount.'

'Did he? They had some dealings in the past, I know, but Bealknap was too shady for Marchamount's liking.'

'Marchamount moves in semi-papist circles. That worries me. Question him too. Threaten him or flatter him or offer him gold, I don't care so long as you loosen his tongue.'

'I'll try, my lord. And the third-'

'Marchamount took the story to a mutual acquaintance of ours. Lady Bryanston.'

My eyes widened in surprise. 'I met her only a few days ago. She invited me to dinner.'

'Yes, I dropped your name at her table last week, when I was thinking of employing you to get the formula from Gristwood. That is good, you must go. Talk to her too.'

I reflected a moment. 'I shall, my lord. But if I am to get to the root of this matter-'

'Yes?'

'I need to know more about Greek Fire. Retrace the steps from its discovery to the demonstrations you held.'

'If you think fit. But remember, time presses. Barak here can tell you all about the demonstrations, he can take you out to Deptford to see where they took place.'

'And I could talk to the monastery librarian. Perhaps visit St Bartholomew's to see where the stuff was found.'

He smiled coldly. 'You don't believe in Greek Fire yet, do you? You will. As for Bernard Kytchyn, Brother Bernard the librarian as he used to be, I've been trying to trace him since Lady Honor first came to me. To make sure he kept his mouth shut too. But like half these ex-monks he's disappeared without trace.'