We stalked upstairs, constantly listening. One by one we flung open doors. Empty salons and deserted bedrooms. Dust undisturbed on pediments. Woozy flies flinging themselves against closed windows in warm solitude.

Gordianus was in the last room of the first corridor we explored. He had slumped against the marble dado and we thought he must be dead. Not so; only despairing.

'I had him-I got my knife in him-but he attacked me and I bungled it…'

Checking him over for physical damage, I muttered sympathetically. 'There's a world of difference between dispatching something woolly at the altar, and taking human life-' Pertinax had belted the Chief Priest viciously against a wall. Not much surface bruising, but at his age shock and exertion were taking their toll. He was having such difficulty breathing I worried for his heart.

I joined Milo in carrying the priest downstairs, and hurriedly let them out together. 'Milo, you look after him.'

'I'll come back-'

'No. What's here is mine.'

He helped make a pressure pad and bind up my side with the white veil I had worn at the ceremony. Then I watched him and Gordianus leave.

This was how I wanted it: Pertinax and me.

•

Inside the house again I relocked the door behind me. Pertinax probably had his own key when he had lived here, but it was no use to him now. When I act as an executor, the first thing I do is fix new locks.

I walked from the door slowly. One of us might leave that way eventually. It was the only door. This was a rich man's mansion. Rome was alive with cat burglars, and this gem of a property had been built for multimillionaires with treasures to protect. The external walls were completely blank for security. The windows faced inwards. All the light which flooded in came from internal courtyards and the open roof of the atrium. What happened in the streets outside belonged to another world.

He was here. So was I. I had the key. Until I found him, here we would both stay.

I started to search. There were scores of rooms and in some places there were passages where he could slip past me, so I had to patrol some areas twice. I took a long time. My wound started to burn and bother me. Blood was oozing through the cloth. I trod quietly, to avoid warning him and to conserve my own strength. Gradually I covered every room. And in the end I remembered the one place I had missed; so I knew where he must be.

I walked slowly down the red corridor for a second time. My boots slipped unwarily on the shining, level tessellation of the passageway floor. I stepped between the two plinths where basalt portrait busts had once stood, and into the elegant azure and grey bedroom that had once been a private haven for the lady of the house. The warm, deep blue of the wall panels welcomed me graciously. I felt like a lover, treading an accustomed secret route.

I noticed a small, rust-coloured smudge staining the geometric pattern of the silver and white mosaic. I knelt, with some difficulty, and touched it with my finger. Dry. He had been hiding here a long time. Perhaps he was dead.

Hauling myself upright, I dragged my tired feet over to the wooden folding door. It was closed. But when I opened it, from the far side of Helena's garden his angry eyes met mine.

I limped to a stone border and edged myself painfully into a half-sitting position facing him. 'Couple of wrecks!'

Pertinax grimaced, eyeing up my own condition as he struggled to ease himself. 'What happens now, Falco?'

'One of us will think of something…'

He was in the shade. I was in the sun. If I moved to avoid it the fig tree would block my view of him. So I stayed.

He was the fidgety, hasty type; I had plenty of time. He fell silent watching me from that taut, narrow face.

'Your wife's garden!' I carolled, looking round. It was a small peristyle, full of muted sunlight and rich greenery. On one side of the colonnade, a worn stone seat with lion's paws. Low, sculptured hedges, with the faint scent of rosemary where I had crushed bushes as I found somewhere to perch myself. A thin trail of laburnum. And a small statue of an urchin pouring water-a ragamuffin in a patched tunic-who looked as if Helena might have chosen him herself.

Helena's garden. A good-tempered, mature little courtyard, as quiet and civilized as she was. 'This is a peaceful, private place for a talk,' I told him. 'And a good, private place for a man who doesn't exist anyway to die… Ah, don't worry. I promised your wife-your first wife-not to kill you.' I let him relax, then put iron in my voice: 'I'm just planning a series of hard, non-fatal blows that will persuade you staying alive is so painful you will finish off yourself!'

The priest had made a decent start of it. Better this way; some deaths need time.

He was on the ground, sideways to me, leaning on one hand. Almost no position was comfortable. He had to twist into the hasp of the wicked religious knife Gordianus had prodded into his ribs. He wanted to hold it firm. If he pulled it free, the rush of blood might bear his soul away. Some men would take the risk; I would have done.

I said, 'A military surgeon could safely get that out of you.' Then grinned, to let him know I would never let a surgeon into the house.

He was white. So was I, probably. Tension does that.

He thought he was going to die. I knew he was.

•

My eyes drooped. I saw him move, hopefully. I opened my eyes again, and smiled at him.

'This is pointless, Falco.'

'Life is pointless.'

'Why do you want me dead?'

'You'll see.'

'Today was pointless,' Pertinax mused. 'Why the trick with the barmaid? I can repudiate the marriage as soon as I want-'

'Got to get out of here first, sir!'

He thought about the marriage bitterly, ignoring me. His old restless bad temper jerked behind those pale, turgid eyes. His face had grown gaunt with his obsessions-that sense of outrage, not at his own failure, but at the world's refusal to give him recognition. His was a soul inching into madness. But he was not mad yet. I judged him still capable of answering for his crimes.

'Did my wife arrange this?' he demanded, as if the sunshine of sudden understanding had flooded him.

'Your first wife? She has the brains, but is she that vindictive, sir?'

'Who knows what she would do!'

I knew. In any situation I could make a fair guess: look for the obvious, then look for the oddest deviation from it and there would be Helena. Helena, making her quaint choice appear to be the only course anyone with any culture and moral fibre could take. He had owned her for four years whilst she struggled to do her duty by them both-yet he did not know the first thing about that eccentric mixture he called his wife.

'Helena Justina wanted to help you. Even when she knew you were a traitor and a murderer-'

'Never,' he stated briefly. 'This was the one thing I asked her to do for me…' He watched me easing the bloodstained cloth around my ribs. 'We could help each other, Falco. Neither of us stands much chance alone.'

'Mine's a scratch on the surface. You're bleeding internally.'

Whether he was or not, the threat frightened him.

'Your wife's no fool,' I said, taking his mind off his terror of death. 'She told me, in Campania, "Every girl needs a husband!".'

'Oh she does!' exclaimed Pertinax. 'Did she tell you she picked up a pregnancy?' He said it as if he meant a heat rash she had caught on holiday.

'No,' I replied calmly. 'She never told me that.'