Another movement caught my eye. A helmet flashed, among the Praetorians assembled on the temple step. Oh no.

The Chief Spy had been visiting Ma just before me yesterday. She must have told him what she told me. Now Anacrites and some of the Guards were on the move, and I could guess where they were all going. They too were heading to the Temple of Diana Aventinensis – and they would probably arrive ahead of me.

XL

The senator had half risen from his seat. He liked heroics. Helena Justina pushed him back. 'Marcus, take me!' 'No.' I did not want to tell her that it might be dangerous. 'Stop shutting me out, Marcus.' She would never change. She had tamed a reprobate, settled down, borne two children, run a household – but Helena Justina would never become a respectable matron, satisfied with domesticity. We first met during an adventure. Action formed part of our relationship. Always did, always would do.

She and I shared a tussle of wills, which I enjoyed more than I should have done. As I looked into those determined dark eyes, she nobbled me as she always did, and 1 felt a smile twitch. 1 wanted her to be safe – yet I wanted her to come. Helena spotted my weakness. At once she whipped off the costume wig. Her own fine hair had been pinned up under it, but escaped in a whoosh. She wore little jewellery; with the plain brown dress under a plainer cloak, she would be anonymous on the streets. That was obviously planned. She bent down, mouthing in her mother's ear, 'We are just going to look for -' 'Oh pee on a column, Marcus! Be like everybody else.' Bright-eyed, Helena exploded into giggles. 1 grinned at the senator over Julia Justa's head, as she burrowed in her hamper again, oblivious. Camillus Verus, trapped there at the banquet, shot us an envious look. Then I clutched Helena by the hand and we left. We ran into Titus Caesar. Youthful, splendid in the purple, famously magnanimous, the heir to the Empire greeted us like favourite cousins. 'Not leaving already, Falco?' 'Following a lead on that case, sir.' Titus raised his eyebrows and gestured towards Anacrites. 'I thought it was in hand.' 'Joint operation, sir!' 1 lied. His eyes lingered on Helena Justina, clearly wondering why she was coming with me. 'I always take a girl to hold the cloaks.'

'Chaperon duty!' Helena snorted, as she let Titus see her elbow me hard, correcting my cheeky suggestion. With a jaunty grin for the heir to the Empire, I dragged her away.

Anacrites had been held up. The slaves who guarded the statue were not willing to let him leave the scene until they had checked Saturn over for damage. They milled around the Spy; he was stalled, desperately trying to shake off the unwanted attention without drawing down any more on himselЈ The man was completely incompetent. He would be lucky to escape from his ill-timed trip on the spilled oil without a charge of insulting the god. I did not stay to watch.

We were on foot. In light leather party shoes with sloppy straps and flimsy soles, every uneven pavement tortured our feet. Still, we had no need to mill about making decisions. Our only problem was pushing through the crowds. First the banqueters, who were merrier than they should have been, given how hard it was to find any of the free wine. Then the unfed onlookers, who saw no reason to let people who had an invitation dodge their duties. '10 Saturnalia!' And 10 to you, you gawking menace… We were elbowed and shoved – all in a cheerful spirit, of course – and only escaped after we were bruised and swearing.

I reckoned Anacrites would be heading up the Clivus Capitolinus, so we ducked the other way. I took us through the Arch of Tiberius and the Arch of Janus to the back of the temple, then turned along the dark rear portico of the Basilica. On the Palatine side it was deserted, apart from a few ever-hopeful women of easy virtue, but none tried to approach us. At the far end we took a straight run to the right up the Vicus Tuscus, a swerve as we headed for the Circus Maximus, a rush across the Street of the Twelve Gates. To climb the Aventine, I picked the first steep lane. Temple of Flora, then Temple of the Moon. A veer to the left, a shuffle to the right, and we came out by the Temple of Minerva where I had told Clemens to establish his watch-point. Flanked by enormous double porticoes, the Temple of Diana sprawled at an angle, right next door, just beyond our arrival point.

Everywhere should have been silent and in darkness, but the piazza in front of the temples was ablaze with lamps, music and excited voices. We had picked a bad night. The neighbourhood was choked with a crowd of manumitted slaves, who claimed the goddess Diana as a patron. Their main celebration is supposed to be the slaves' holiday on the Ides of August, the day when the temple was inaugurated centuries before; at Saturnalia, freedmen pull their cap of liberty back on if they are tired of being sober citizens and want another chance to indulge in riotous behaviour. The singing, dancing crowd was intermingled with others whose shyness suggested they were fugitives. If these furtive souls had been hiding up at the temple, they had now ventured outside to party in the streets, thinking the festival gave them security. But I thought I recognised some from my dark adventure on the Appian Way. I certainly knew their alarming habits. A flock of them were swooping around like uninvited guests, obviously trying to unnerve other people.

'Hello, pretty boy!' Clemens greeted me, with a teasing glance at my blue tunic and soft shoes. Dropping the joke, the acting centurion helped a sword belt over my head. Concealing it beneath my cloak, I nestled the familiar weight of the weapon under my right arm. The others were carrying too. It was illegal – but the laws for private citizens in Rome had not been composed to cover occasions when you might have to search the oldest temple recorded by the pontiff, looking for an enemy of the state. 'This is a bit busy, Falco!' 'The night is going to be fun. I warn you, we'll be vying with the Praetorian Guards.' 'Marcus knows how to organise a good night out,' Helena told Clemens, perhaps with pride in me. 'I-o!'

We had a hard time squeezing through the crazy revellers. By the time we reached the altar court below the steep steps to the Temple of Diana, nothing was going as planned. Coming towards us from the gentle dogleg of the Clivus Publicius I now saw Anacrites' litter, presumably with him lolling inside, massaging his twisted ankle. A small armed escort marched behind. The few Guards who had peeled off from imperial duties at the Temple of Saturn would have been a manageable group for us. But I saw with despondence that a much larger force had already formed up here in the compressed outdoor altar space, waiting to rendezvous with the Spy. Pressing forward, Clemens had seen neither the new arrivals nor their waiting phalanx of colleagues. I nudged him hard. 'Hold off! 'Shit on a stick!' he muttered, behind his hand. He hissed an order and the lads pulled up. We edged back, hoping to hide in the crowd.

No luck. Anacrites had seen us. He had his litter carried right alongside. His sleek head appeared through the curtains. 'Falco! You were perfectly right and I should have listened. Your prescience is wonderful.' Sickened by his fake adulation, I stared around for its cause. The Spy pointed happily. Two figures approached at a fast trot from the direction of Fountain Court: Lentullus, with his ears looking big on a shaven head, loping breathlessly after my taller, faster brother-in-law. ' You warned me I did the wrong thing keeping him in custody. I should have let him go myselЈ If the priestess will not come to him,' Anacrites gloated, 'you knew that Camillus Justinus would come straight to her!'