I found myself gripping Helena's arm so tightly I must be bruising her; angrily I released my hold and buffed up her skin. 'You should have told me.'

'I would have done!' she exclaimed hotly. 'You were nowhere around to be told.'

'Sorry.' I bit my lip, annoyed with myself for staying out so long with Musa.

A girl was dead; our feelings were unimportant. Brushing off the quarrel, Helena continued her story. 'To be honest, it seemed best not to rush. Ione gave the impression she had an assignation.'

'With a man?'

'So I presumed. She only said, "I'll go ahead. I've some fun fixed up:" The plan was for me to meet her at the pools ahead of the others, but I didn't hurry because I was nervous about interrupting her fun. I hate myself now; it made me too late to help her.'

'Who else was going?'

'Byrria. Afrania had shown interest, but I was not sure she meant to turn up.'

'All women?'

Helena looked cool. 'That's right.'

'Why did you have to go at night?'

'Oh don't be silly! It wasn't dark then.'

I tried to stay calm. 'When you got to the pools Ione was in the water?'

'I noticed her clothes beside the pool. As soon as I saw her lying still, I knew.'

'Oh love! I should have been with you. What did you do?'

'No one else was about. There are steps at the edge for drawing water. She was there in the shallow water on the ledges. That was how I saw her. It helped me drag her out by myself; I don't think I could have managed otherwise. It was hard even so, but I was very angry. I remembered how you tried to revive Heliodorus. I don't know if I did it properly, but it didn't work – '

I hushed her soothingly. 'You didn't fail her. You tried. Probably she was already dead. Tell me the rest.'

'I looked nearby for evidence, then suddenly I became frightened in case whoever killed Ione was still there. There are fir trees all around the site. I seemed to feel someone watching me -I ran for help. On the way back to the city I met Byrria coming to join us.'

I was surprised. 'Where is she now?'

'She went to the pools. She said she was not afraid of any murderer. She said Ione should have a friend guarding her.'

'Let's hurry then:'

Not long after that we were among the same fir trees that had made Helena feel threatened. We rode under the arch and reached the pools, dimly lit and resonant with the frenzied croaking of the frogs.

There was a large rectangular reservoir, so large it must be used to supply the city. It was divided into two by a retaining wall that formed a sluice. On the long sidesteps led down into the water, which looked deep.

At the far end we could hear people cavorting, not all of them women. Like the frogs, they were ignoring the tragic tableau, too lost in their private riot even to be curious. Ione's body lay at the edge of the water. A kneeling figure kept guard alongside: Byrria, with a face that said she was blaming a man for this. She rose at our approach, then she and Helena embraced in tears.

Musa and I walked quietly to the dead girl. Beneath a white covering which I recognised as Helena's stole, Ione lay on her back. Apart from a heavy necklace, she was naked. Musa gasped. He drew back, shamed by the blatant bare flesh. I fetched a lamp for a close look.

She had been beautiful. As beautiful as a woman could wish to be, or a man yearn to possess.

'Oh cover her!' Musa's voice was rough.

I was angry too, but losing my temper would be no help to anyone. 'I mean the woman no disrespect.'

I made my decisions, then covered her again and stood.

The priest turned away. I stared at the water. I had forgotten he was not my friend Petronius Longus, the Roman watch captain with whom I had surveyed so many corpses destroyed by violence. Male or female made no difference. Stripped, clad, or merely rumpled, what you saw was the pointlessness of it. That, and if you were lucky, clues to the criminal.

Still appalled but controlling it, Musa faced me again. 'So what did you find, Falco?'

'Some things I don't find, Musa.' I talked quietly while I thought. 'Heliodorus had been beaten to overpower him; Ione shows no similar marks.' I glanced quickly around the spot where we stood. 'Nothing here implies the taking of drink, either.'

Accepting my motives, he had calmed down. 'It means?'

'If it was the same man, he is from our company and she knew him. So did Heliodorus. But unlike him, Ione was quite off her guard. Her killer had no need to surprise or subdue her. He was a friend of hers – or more than a friend.'

'If her killer was the person she had been prepared to name to you, it was rash to arrange to meet him just before she spoke of it to Helena.'

'Yes. But an element of danger appeals to some -'

'Marcus!'

Helena herself suddenly said my name in a low voice. A reveller with a conscience may after all have reported a disturbance. We were being joined by one of the sanctuary servants. My heart sank, expecting inconvenience.

He was an elderly attendant in a long striped shirt and several days' growth of whiskers. In one dirty claw he carried an oil flagon so he could pretend to replenish lamps. He had arrived silently in thonged slippers, and I knew straight away his chief pleasure in life was creeping about among the fir trees, spying on women frolicking.

When he shuffled into our circle both Musa and I squared up defensively. He whipped aside the stole and had a good look at Ione anyway. 'Another accident!' he commented in Greek that would have sounded low-class even on the Piraeus waterfront. Musa said something curt in Arabic. The curator's home language would be Aramaic, but he would have understood Musa's contemptuous tone.

'Do you suffer many deaths in this place?' My own voice sounded haughty, even to me. I could have been some stiff-necked tribune on foreign service letting the locals know how much he despised them.

'Too much excitement!' cackled the lecherous old water flea. It was obvious he thought there had been dangerous fornication, and he assumed Musa and I, Helena and Byrria, were all part of it. I ceased to regret sounding arrogant. Wherever they are in the world, some types cry out to be despised.

'And what is the procedure?' I asked, as patiently as I could manage.

'Procedure?'

"What do we do with the body?'

He sounded surprised: 'If the girl is a friend of yours, take her away and bury her.'

I should have realised. Finding a girl's naked corpse at the site of a promiscuous festival at the end of the Empire is not like finding a corpse in the well-policed city sectors of Rome.

For a second I was on the verge of demanding an official enquiry. I was so angry, I actually wanted the watch, the local magistrate, an advertisement scrawled in the forum asking witnesses to come forward, our own party to be detained pending the investigation, and a full case in court in half a year's time: Sense prevailed.

I drew the greasy curator to one side, palming across as much small change as I could bear.

'We'll take her,' I promised. 'Just tell me, did you see what happened?'

'Oh no!' He was lying. There was absolutely no doubt about it. And I knew that with all the barriers of language and culture between Rome and this grubby pleasure ground, I would never be able to nail his lies. For a moment I felt overwhelmed. I ought to go home to my own streets. Here, I was no use to anyone.

Musa appeared at my shoulder. He spoke out in his deepest, most sonorous voice. There was no threat, simply a clean-cut authority: Dushara, the grim mountain-god, had entered this place.

They exchanged a few sentences in Aramaic, then the man with the oil flagon slithered away into the trees. He was heading for the noises at the far end of the reservoir. The merrymakers' lamps looked bright enough, but he had his own unsavoury business there.