Like Cleopatra before her, Veleda was determined not to be made a spectacle for the Roman crowd. I muttered to Helena, 'Luckily the Bructeri have never heard of asps.'

Ganna said Veleda had made up her mind to escape immediately and being both determined and ingenious, she did so. She went alone. It was very sudden. Ganna was left behind; in the hurried investigation that followed, she was terrified to learn that the Chief Spy intended to interrogate her, probably using torture. She took advantage of the confusion at the Quadrumatus house and also ran away, not knowing where she could find her companion or how to survive in a city. Veleda had told Ganna that there was one man in Rome who might help them return to the forest, giving her my name.

I like to be thought of as a man of honour – but returning these women to the wild woods a thousand miles to the north would be harder than Ganna seemed to realise. For a start, the logistics would be appalling. But I had no intention of allowing either to go back to the Free German tribes, carrying yet more stories of Roman duplicity. Even if I could manage it, if the truth came out here, I would be a traitor, crucified by a high road and damned to the memory.

There was more. With extra tears and entreaties Ganna wrung her hands and beseeched me to help with a desperate problem. She wanted me to find Veleda before harm befell her

'This is a very serious request,' I said gravely. Helena Justina glanced across sharply. I always loved having duplicate commissions, if they came with a double fee. 'And for a private informer, perhaps it is inappropriate.' Helena shot me another sarcastic glare.

It did not stop Ganna. She was determined that I was the man for the business – for much the same reason as Laeta had been: I knew Veleda. Ganna believed that would make me sympathetic towards her missing companion, for whom she expressed worse anxieties. With more of those entrancing tears running down her pale face from her delicate blue eyes, Ganna said that ever since Veleda had arrived in Rome, she had been suffering from a mysterious illness.

Veleda was sick? That really was bad news. Captives who are destined to adorn famous generals' Ovations are not supposed to pass away from natural causes first.

It was bad news for me too. 'Abate the fee' was the Flavian emperors' motto: I would lose the extremely generous reward I had been promised by Titus Caesar if, when I produced Veleda, she was already dead. I told Ganna I was obliged to work for money and she assured me that she had it to give. She left her gold torque as a surety. I say 'left' because I quickly moved her out; I was uneasy about keeping her at our house. Apart from Albia's hostility, there was the coming problem of ten disgruntled brutes from the German legions. They would know who Ganna was and might report us to the authorities for harbouring a fugitive. Helena knew nothing about them yet, so I kept quiet about the soldiers.

I persuaded my mother to take in the blue-eyed forest virgin. Ma was suffering badly from cataracts; although she hated needing a guide around her own kitchen, she was in so much trouble with her vision, she admitted she could use help. Ganna knew nothing of Roman domestic procedure now – but by the time my mother had finished with her, she would. It amused Helena to think of her one day returning to the wilds of Bructeran territory, able to make an excellent pounded green-herb dip. In Free Germany, she would never be able to find the rocket and coriander to show off at the tribal feast, but she would spend the rest of her life dreaming of Ma's egg white chicken soufflй…

I wanted Ganna kept somewhere under my control. Apart from the fact that it would salt her away from Anacrites' clutches, I was not fooled by the tears and hand-wringing. This young lady clearly had something she was not telling us. Ma would keep her under strict guard until either I found out the secret for myself, or Ganna was prepared to tell me.

I was right about her hiding something. When I discovered just what she had omitted from her story, I saw why. She should have known I would find out, though. I was going to the Quadrumatus house next day.

The day opened on a cool, crisp morning with a bite in the air that would make your lungs hurt if you had anything of a cold. Most people in Rome did. It was the time of year when a visit to a public library was orchestrated by coughs, sneezes and snorts as constantly as the rattle of snare drums and rime of flutes at some dimly lit dinner party where your millionaire host's parting presents would include the pretty serving boys. If you didn't have a wheeze when you started the day, you would catch something by your return. I had to walk along the Embankment towards the meat market, where some snotty stallholder was bound to catch me with his filthy spittle as I passed.

I was visiting a senator with consular connections, so I had dressed to a high standard. I was wearing a good woollen cloak, with oily waterproofing, my current best boots, which were leather with bronze tags on the laces, and a seductive Greek Mercury's hat. All I needed was wings on my boots to look like a messenger of the gods. Beneath this striking outer ensemble was a triple layer of long-sleeved winter tunics, two of them almost unworn since the last laundering, a belt with only three buckle-holes ripped beyond use, an empty money purse attached to the belt and a second money purse, half full, hidden between the second and third tunic to thwart any thieves in the Transtiberina. If I wanted to pay for anything that cost more than a bruised apple, I had to show off my privates as I fumbled through these layers of clothing to reach my cash. The swanky outerwear was not because I am impressed by senators, but because their snobbish door porters inevitably reject anyone who looks remotely faded.

I was an informer. I had spent seven years tracing stolen art, helping hapless widows manoeuvre themselves into legacies their ruthless stepchildren coveted, pursuing runaway teenagers before they got pregnant by handsome delivery boys, and identifying the blood soaked killers of nagging mothers-in-law when the vigiles were too busy with fires, chicken races and arguments about their pay to bother. While carrying out this fine work for the community, I had learned all there was to know about the arrogance, awkwardness, ineptitude and prejudice of the bloody-minded door porters of the city of Rome. That was just the ones who decided at first sight they disliked my chirpy face. There were also plenty of sloths, gossips, drunks, petty blackmailers, neighbourhood rapists and other scallywags out there, who were just too busy with their personal careers to let me in. My only protection was to find out that a porter was having a passionate affair with the lady of the house so I could threaten him with revealing all to his jealous master. It rarely worked. In general the debauched mistress couldn't give two figs whether her antics were known, but even if she was terrified of exposure, the door porter was usually so violent the betrayed master would be scared of him.

I had no reason to think Quadrumatus Labeo had a porter who fell into any of those categories, but it was a good stroll to where he lived so as I loped along I amused myself with the lore of my craft. I liked to keep the brain active. Especially in cold weather, when my feet were so cold from tramping the travertine that thought became too tedious. The last thing an informer needs is to arrive for a big interview with his once-incisive mind frozen like a snow-sorbet. Preparation counts. No point in meticulous planning of penetrating questions if you lapse into a coma as soon as they give you a warm welcoming drink. The best informer can be lulled into uselessness by slurping an insidious hot wine toddy with a lick of cinnamon.