She looked at him narrowly. 'Are we prisoners, then?'

'They are for your protection, madam. You may still not be safe.'

She removed her coif and ran her fingers though her grey hair, then gave Barak a hard stare. 'What about my front door? Anyone could get in.'

'It will be repaired.' He spoke to one of the retainers, a hard-looking fellow. 'See to that, Smith.'

'Yes, Master Barak.'

He turned back to me. 'Lord Cromwell wants a meeting now. He's gone to his house in Stepney.'

I hesitated. Barak stepped closer. 'That's an order,' he said quietly. 'I have told my master the news. He is not a happy man.'

RIDING THROUGH the City again after being in that silent house of death, I felt strangely disconnected from the jostling, noisy crowds. We had a long way to go, for Lord Cromwell's house at Stepney was far beyond the City wall. We paused only to allow a procession past – a cleric in white robes leading a man dressed in sackcloth, ashes strewn over his face and carrying a faggot, the church congregation following behind. Someone whose reformist opinions had been deemed heretical but who had repented, the ashes and the faggot reminders of the burning that awaited him if he relapsed. The man was weeping – perhaps it had been a reluctant recantation – but if he sinned again his body would be weeping blood as the fire shrivelled it.

I glanced at Barak, who was eyeing the scene with distaste. I wondered what his religious opinions were. It had been quite a feat for him to reach Cromwell, collect these men and get back to Queenhithe so quickly. Yet he did not look tired, though I felt exhausted. The procession shuffled past and we moved on. Thankfully the afternoon shadows were lengthening, the overhanging houses bringing a welcome shade to the streets.

'What's that in your pocket?' Barak asked as we rode up Bishopsgate.

I put my hand to my robe and realized that I had slipped Sepultus's book there without thinking.

'It's a book on alchemy.' I looked at him fixedly. 'How you watch me. You thought the formula might have been with those papers I gave to Goodwife Gristwood?'

He shrugged. 'Can't trust anyone these days, not if you're in the earl's service. Besides,' he added with an insolent smile, 'you're a lawyer and everyone knows you have to keep an eye on lawyers. Not to do so would be crassa neglegentia, as you people say.'

'Gross negligence. You have some Latin then?'

'Oh yes. I have Latin, and know men of law. Many lawyers are great reformers, are they not?'

'Ay,' I replied cautiously.

'Is it not amusing, then, now that the monks and friars have gone, how the lawyers are the only ones to walk around in black robes, calling each other brother and trying to part people from their money?'

'There have been jokes against lawyers time out of mind,' I said shortly. 'They become tiring.'

'And they take oaths of obedience, though not of chastity or poverty.' Barak smiled mockingly again. His mare wove quickly through the crowds and I had to spur poor Chancery to keep up. We passed under the Bishopsgate and soon the chimneys of Cromwell's impressive three-storey house came into view.

The last time I had been there, on a bitter winter's day three years before, a crowd of people had been waiting at the side gate. Another crowd was there this hot afternoon. The outcasts of London, shoeless and in rags. Some supported themselves on makeshift crutches, others had the pits and marks of disease on their faces. The number of workless poor in London was growing beyond control; the dissolution had cast hundreds of servants from the London monasteries, and the unhappy patients from the hospitals and infirmaries too, out onto the streets. And pitiful as the doles given by the Church had been, now even those were gone. There was talk of charitable schools and hospitals, and schemes for state works, but nothing had been done yet. Cromwell, meanwhile, had adopted the wealthy landowner's custom of distributing his own doles; it strengthened his standing in London.

We rode past the beggars and through the main gate. At the front door a servant met us. He asked us to wait in the hallway, then a few minutes later John Blitheman, Lord Cromwell's steward, appeared.

'Master Shardlake,' he said, 'welcome. It has been a long time. Does the law keep you busy?'

'Busy enough.'

Barak, who had untied his sword and handed it with his cap to a servant boy, came over.

'He's waiting for us, Blitheman.' The steward smiled at me apologetically and led us into the house. A minute later we were outside Cromwell's study. Blitheman knocked softly and his master called, 'Enter,' in a snapping tone.

The chief minister's study was as I remembered, full of tables covered with reports and drafts of bills, a forbidding place despite the sunlight streaming in. Cromwell sat behind his desk. His manner was different from what it had been that morning; he sat crouched in his chair, head sunk between his shoulders, and gave us a look so baleful it made me shiver.

'So,' he said without preliminaries, 'you found them murdered.' His voice was cold, intense.

I took a deep breath. 'Yes, my lord. Most brutally.'

'I've got men searching for the formula,' Barak said. 'They'll take the place apart if need be.'

'And the women?'

'They'll be kept there. They're both scared out of their wits. They know nothing. I've told the men to ask round the neighbouring houses to see if anyone saw the attack, but Wolf's Lane looks like a place where people take care to mind their own business.'

'Who betrayed me?' Cromwell whispered intently. 'Which of them?' He stared at me fixedly. 'Well, Matthew, what did you make of what you saw?'

'I think there were two men involved and that they broke in with axes. They killed the brothers at once in the alchemist's workshop, where they were working, then went to a chest that was kept there and smashed it in. There was a bag of gold inside, but they left it untouched.' I hesitated. 'My guess is that the formula was there and they knew it.'

There was a grey tinge to Cromwell's face. He set his thin lips.

'You can't be sure,' Barak interjected.

'I'm not sure of anything,' I replied with sudden heat. I made my voice calm. 'But no search was made of the rest of the room. The books on the shelves were undisturbed and would they not have been an obvious place to look for a hidden paper? Also, I believe some bottles were taken from the shelves. I think the people who murdered those poor men knew exactly what they were looking for.'

'So there will be no physical traces left of their experiments,' Cromwell said.

'That would be my guess, my lord.' I looked anxiously at him, but he only nodded reflectively.

'See, Jack,' he said suddenly, nodding at me. 'Learn from a master of observation.' He turned bleak eyes on me again. 'Matthew, you must help me solve this.'

'But, my lord-'

'I can't tell anyone else,' he said with sudden passion. 'I daren't. If it got to the king-' He sighed, a shuddering sound. It was the first time I had seen Thomas Cromwell afraid.

'You must solve this,' he repeated. 'You can have any authority, any resources.'

I stood on the fine carpet, my heart thudding. Once before he had sent me to investigate a killing, pitching me into horrors beyond imagining. Not again, I thought. Not again.

He seemed to read my mind and sudden anger flashed in his eyes. 'Christ's wounds, man,' he snapped. 'I've saved that girl's life for you. Or at least I'll save it if you help me; Forbizer can be made to change his mind again if need be. My own life could be at stake here as well as everything you once believed in.' I had a momentary vision of Elizabeth, lying blank-eyed in her cell. And I knew that at a word from Cromwell I could be flung in gaol too, for knowing too much.