'You'd better get to the Spy's house before the Germans do,' said Petro, with rather too much interest. I wondered how much he had drunk this evening. More than I had thought, apparently. He looked ready to rob temples of their treasure, if some bright maniac suggested a romp. He was up for anything.

All the same, I had no intention of stopping him, if he was prepared to help. We thought about the situation. That is, we both thought but only for the time it took to close our eyes and groan. 'You could just warn Anacrites.' 'And party on? How civic.' I knew 'civic' would be an insult to Lucius Petronius.

'Rats. Are you on, Falco?' You might imagine I had to beg him for help, but Petronius, that madcap adventurer, had already decided to involve himself and was checking with me.

I buried my surprise. 'Pity to miss the lads' night out.'

'Oh don't worry.' Petro appeared to do calculations. 'The night is young. We should have time to manage it: gather some back-up, break into the Spy's house, grab Camillus, hide him somewhere private – and still get back to the party before the wine runs out.'

XXXIV

Anacrites' house lay in darkness, apparently. A small group of us assembled silently in the street below the Palatine and surveyed the area. For once the Forum, behind us, seemed deserted. No lights showed at the house; the gates were barred. It looked the same as when I came here before in the dead of night, though that was no guarantee that the Spy was away from home. It was not essential that he should be out tonight, but it would be safer for us if he was. As we walked here, I had suggested we devise a plan. No need: Petronius Longus already had one. My mend was a man of surprises. I could not even remember telling him that Anacrites was holding Juscinus, and why, but Petro seemed to know all about it. When I had discussed this situation with the senator and with Helena, I had decided it was easiest to leave Justinus here, reading endless Greek plays. But since the German guards were trying to lift the prisoner, Petronius saw there was a need for radical action. His plan was: pretend the vigiles had smelt smoke at the house, cry 'Fire!', then use their legal authority to march in, conduct a search for human life, find Justinus, and haul him out. 'Rescue him like a house fire victim. Simple, eh?' 'You mean, thought up by a simpleton? It will never work.' 'Watch us,' said Petro, giving the nod to Fusculus and whistling a signal to some of his lads.

The first stage went as I expected. A couple of vigiles were given a leg-up; they climbed over the high wall, taking a covered lantern they had conveniently brought with them. Deep-throated guard dogs started barking almost at once, then abruptly fell silent. The lads returned unscathed and said they had set fire to some piles of leaves. I was puzzled by what happened next: Petronius let out a loud whistle, of the kind the watch use to signal for reinforcements when they detect a fire during their night rounds. Instead of rushing straight to the front door, we just settled unobtrusively into the shadows and kept quiet. 'Aren't we going in?' 'Shut up, Falco!' After a while, when nothing happened, Petro muttered derisively then whistled again, louder. This time we heard swiftly marching feet. A regular bunch of vigiles came around a corner, heading for our location. Petronius stepped out into the light of their flares. 'Oh officers, I am so glad to see you. I was just on my way to a party with a group of friends when we smelt smoke. It seems to be coming from that house over there…' 'Have you roused the household, sir?' 'Can't get any answer. They probably think we are drunks causing trouble and don't realise we are public-spirited citizens.' 'Well, thank you. You can leave it to us now. Don't worry, sir; we'll soon have it sorted-'

Petronius grinned to me. 'Sixth Cohort. We're in their jurisdiction. There are rules, you know, Falco.' In fact I knew he was not fond of the Sixth and would cheerfully implicate them in what was to follow, rather than his own cohort – just in case things went wrong. The men he had spoken to knew exactly who he was. Somehow he had persuaded the gullible Sixth to do him a favour.

Loud bangs on the door produced household slaves, whose protests that there was nothing wrong were brushed aside in the usual kindly vigiles manner – that is, the slaves were knocked to the ground, kicked into submission, and pinned down on suspicion of being arsonists. The Sixth then rushed inside to search the building, as fire-fighters were entitled to do whenever the alarm was sounded. The household slaves were now going nuts, perhaps because they realised this would entail the customary 'check on valuables'; they may have feared that afterwards there would not be quite so many valuables in their master's possession as he had owned when the fire started. The slaves knew Anacrites would blame them for any losses and they knew how spiteful he could be.

By now there really was a fire. Apparently when Petro's men kindled a damp pile of leaves for a false alarm, it led to shutters blazing and showers of sparks in roof spaces, all in a matter of minutes. Perhaps they had been over-enthusiastic, Petronius commented gravely. At any rate, Anacrites' house was now filled with thick smoke. Heavily equipped members of the Sixth Cohort were running around with the buckets, ropes and grapplers they always carried. With commendable speed, their siphon engine turned up in the street; any owner of property would be overjoyed to receive such a fast response to his emergency – a privilege few actually receive. But we were in the Palatine and Circus Maximus sector, where many buildings are state owned and even private houses tend to belong to men who know the Emperor personally. A cart laden with esparto mats also appeared – so laden it could hardly teeter along.

'It's almost as if the Sixth were expecting this fire!' I muttered. Petronius shot me a reproving look.

Then – was there a signal? – he grabbed my arm and ran towards the house. I followed as he dashed into the building. The smoke was real, choking us as we plunged down corridors. Ahead of us the vigiles had thrown open doors to check rooms for occupants. Coughing slaves were still being hustled out past us by members of the Sixth, who were shouting at them loudly and pushing them around; it was a tactic to subdue and confuse them. We ran on. Nobody interfered with us.

We passed through formal areas with subdued black and gold paint, a tiny courtyard with a bubbling fountain, then suddenly we were among decadent rooms in the interior, with frescos depicting intertwined couples and threesomes that would not be out of place in a brothel. We reached a narrow passageway where a vigilis was battering at a locked door while being harassed by two large baying dogs; the man kicked at them in annoyance, then hurled a hatchet at the door panels hard enough to split the wood and gain a purchase. Petronius picked up a small marble-topped table and bashed a bigger hole with that. Splintered panels soon gave way to shouldering.

The room contained a collection of the kind of art men keep in private salons with the door locked 'so as not to excite the slaves'. Thereby making secret pornography sessions more exciting for themselves.

There was less smoke in this part of the house. When we turned away in disgust from the art collection, we were able to see the young man who opened a door further down the corridor and looked out to investigate the commotion. It was Camillus Justinus.

At once, according to the vigiles' rules of duty, he was taken hold of roughly, knocked semi-conscious when he protested, then passed from hand to hand in a businesslike fashion as far as the exterior of the building where – in circumstances that were later vague – he vanished. Among many rumours that circulated later about the fire at the Chief Spy's house, I did hear that when the Sixth Cohort came to pack up their esparto mats for return to their patrol house, they discovered someone had filched the mat-cart. And it was said, no doubt mischievously, that towards the end of the incident, Anacrites turned up and was outraged to receive a report on the damage to his house from a man dressed as a five-foot carrot. The Sixth Cohort indignantly denied all knowledge of this vegetable.