We would not find out. The carriage had finally rumbled to the outskirts of the city. It lurched into the hiring stables and we all had to tumble out, Aedemon setting down one heavy limb at a time, then extracting his body from the carriage with a surprisingly lithe shuffle. As he straightened up, he was huffing alarmingly. Helena and I offered to walk with him, but he claimed he had a litter waiting nearby and was not going in our direction. Since we had not said where we were heading, either he was glad to end our interrogation because it strayed into dangerous areas – or he was just bored with our company.

XXXII

It was dark now. I walked us fast from the stables to our house. The season's misrule had begun. Barrow-wheelers and stallholders in the Transtiberina thought that meant asking women – respectable women who were promenading with their husbands – for a quickie up an alley. Helena took it in silence, but she was obviously rattled. Not as much as I was, to be put in the role of her pimp. We had hardly recovered when we were accosted by a six-foot scallywag in his sister's dress, with heavy eyeliner and rouge, and sporting a ridiculous woollen wig with yellow plaits. 'Get away from us! You look like a damned doll.' 'Oh, don't be like that, darling… Give us a cuddle, legate.' 'I'm not your darling, sweetheart. Compliments of the season – and take yourself off or you'll get a Saturnalia gift you won't like.'

'Spoilsport!' The burly demoiselle stopped pestering us, though not before bombarding us with festive vegetables. I threw them back, with a better aim, and he scampered away. 'I hate this festival!' 'Calm down, Marcus. It's like this in the Transtiberina all the time.' 'There must be better ways to celebrate the end of harvest and the planting of a new crop than letting slaves play dice all day and demented cabbage-sellers dress up in girls' clothes.' 'It's for children,' murmured Helena. 'What? Demanding even more presents than usual? Eating their little selves sick on cake? Learning how to put out the fire by pissing on the hearth? – O Saturn and Ops, how many burned bottoms will doctors have to treat next week? – And so much for ending quarrels and wars – there are more unnatural deaths over Saturnalia and New Year than any other working or holiday period! Merriment leads to murder.'

Helena managed to get a word in: 'Gratianus Scaeva wasn't murdered in the festival.' 'No.' Plenty of people would have hangovers this week. Few would decide that decapitation was a reliable cure. Helena had sidetracked me neatly.

Was the timing of events at the Quadrumatus house significant? I couldn't see it. Veleda was not engaging in the spirit of misrule. She might have had the joyful feast of Saturn explained, but Roman celebrations would mean nothing to her. Did the German tribes glorify the revival of the light? Did they honour the unconquerable sun? All I knew was that those bombastic bastards loved a fight. Suspending grudges, whatever the month, was not in their character.

Veleda's gods were spirits of forest and water. She had been a priestess of the mystic presences in glades and groves. Spring and pool nymphs. They were celebrated by gifts – deposits of treasure, weapons, money – laid at sacred spots in rivers and marshes. And yes, these gods were also honoured by depositing the severed heads of enemies in water. But if there was a special season for it, other than in any time of war, I did not know when. To me, if Veleda killed Scaeva, the fact that it happened now appeared to be irrelevant.

If Scaeva's killer was somebody else, as I still thought most likely, they had hardly been overcome by the normal rages of the festival. No brooding uncle finally lost himself, driven crazy because everyone else was enjoying a good time, so he went for Scaeva. Miserable uncles, in my experience, stick it out and inflict their depression on you year after year. They never bring presents, because they 'aren't feeling quite up to it this time' (same as last year's excuse from the miser). All they are up to is swigging the best wine. They don't do anything bad enough to get themselves completely banned, though; they don't kill people.

And no disillusioned girlfriend had launched herself on Scaeva in festival jealousy; we knew the women he had dallied with accepted his attentions as a fact of life; and they liked him, at least for his generosity.

Anyway, the festival had not yet started. I could not make any of this fit… Well, I had a feeling I would end up being wrong, but if Saturnalia was important, it wasn't showing up on the evidence I had scraped together so far. At home, the fun was at hand. Our two slaves, Galene and Jacinthus, had given up all attempts at work, an aspect of the festival they found greatly attractive. Legionaries were hanging green boughs everywhere. I guessed they had spent all day acquiring the foliage, cutting it to size and weaving garlands, instead of continuing the hunt for Veleda. Dinner was progressing; two of the soldiers, Gaius and Paullus, were cooking away happily, watched by our daughters. Julia was singing what I recognised, even through her half-chewed mouthful of mustcake, as a verse from the Little Mess Tin Song. Luckily it was one of the clean verses. Luckily too, Helena gave no sign of recognising the song. From evidence on their tunics and faces, both children had been tasting stuff in the kitchen all afternoon and would not want their proper food. Someone had given Favonia a sigillarium, one of the pointless earthenware figurines that are sold in hundreds for reasons no one can remember; she was using it as a teething device. As I entered the room, a broken piece choked her. Swift action – upending the darling with a sharp smack on the back – remedied that in time in the traditional way. Sensing terrified parents who had thought they had lost her, Sosia Favonia began screaming for more attention. The soldier Paullus remedied that, also in the traditional way: by offering her a big stuffed date. Triumphant, Sosia gobbled it with perfunctory thanks, while Julia began screaming because she hadn't been given one. I left. My excuse, which Helena received much too frostily I thought, was needing to see Petronius Longus about whether any civic-minded citizen had apprehended the runaway flute boy and handed him over to the vigiles. 'Seeing Petro was always on today's list.' 'Can't you do it tomorrow?' 'Could be vital. Why would the boy run away? Maybe he saw something -' 'He saw a headless body in a room full of blood, Marcus!' 'If he thinks Veleda killed the young master, he should feel perfectly safe now that she has left. I suspect he isn't only shocked by discovering the body. He is terrified by something else. This boy is a key witness.' 'Well he's a fine excuse for you!' Helena scoffed. 'Don't bother to promise me you won't stay out long.'

I did promise. I always do. I never learn. Fortunately women learn very quickly, so Helena would not be disappointed when I failed to come home. Petro was not at the patrol house; nobody was, except the clerk. 'Give me the details, if you must, Falco – but be quick! Are you reporting him for his master? I'll need full details of the owner -' 'What for? I don't need to find the master, just the boy. He's a material witness to a homicide -' 'Was he a trained virtuoso? Exceptionally beautiful physical specimen? Did he steal the expensive flute when he ran away?' 'All you bastards care about is valuable property.' 'You get it.' 'Listen, you melon seed, he's traumatised by what he witnessed, he's a vulnerable teenager, he's lost, he's scared, and I think he can tell me something about a gory killing that has deep political overtones.'

The clerk sighed. 'So what's new? All your cases are like that. It's obvious: he saw something. Now he's scared someone may come after him – so work it out, Falco. He must have seen the killer at the scene. He knows who it is, and they either come visiting – or they even live at the house.' That pulled me up. 'Slow down. Your job is to take shorthand notes. I'm the investigator.' 'I think like Petronius Longus, Falco. I've written up his case notes often enough.' 'All the more reason to find this boy urgently.' 'I'll do a memo tomorrow and have the lads look out.' 'Aren't you going to check if he's already in your holding cell?' 'He isn't.' 'How can you be sure?' 'I am sure,' explained the clerk meticulously, 'because the cell is empty. '