I shook my head.

'You will,' he said mysteriously. 'No, politics will never kill this old man for you. Sulla may fill up the Forum with heads on sticks, the Field of Mars may become a bowl of blood tipping into the Tiber — you'll still find the old man traipsing about after dark in the worst parts of town, stuffed from a dinner party at Caecilia's, blithely on his way to the neighbourhood whorehouse.'

Cicero abruptly sat down. The machine, it seemed, needed an occasional rest, but the cracked instrument continued to play. 'So you see that fate will not cooperate in taking the odious old man off your hands. Besides, it may be that there's some urgent reason that you want him dead — not just hatred or a grudge, but some crisis immediately at hand. You have to take action yourself.'

'You suggest that I murder my own father?'

'Exactly.'

'Impossible.'

'You must.'

'Un-Roman!'

'Fate compels you.'

"Then — poison?'

He shrugged. 'Possibly, if you had the proper access. But you're not an ordinary father and son, coming and going in each other's household. There's been some bitterness between you. Consider the old man has his own town house here in Rome, and seldom sleeps anywhere else. You live at the old family home in Ameria, and on the rare occasions when business brings you into the city, you never sleep in your father's house.

You stay with a friend instead, or even at an inn — the quarrel between you runs that deep. So you don't have easy access to the old man's dinner before he eats it. Bribe one of his servants? Unlikely and highly uncertain — in a family divided, the slaves always choose sides. They'll be far more loyal to him than to you. Poison is an unworkable solution.'

The yellow curtain rippled. A gust of warm air slipped beneath its hem and entered the room like a mist clinging low to the ground. I felt it pool and eddy about my feet, heavy with the scent of jasmine. The morning was almost over. The true heat of the day was about to begin. I suddenly felt sleepy. So did Tiro; I saw him stifle a yawn. Perhaps he was simply bored. This was probably not the first time that he had heard his master run through the same string of arguments, refining his logic, worrying over the particular polish and gloss of each phrase.

I cleared my throat. 'Then the solution seems obvious, esteemed Cicero. If the father must be murdered — at the instigation of his own son, a crime almost too hideous to contemplate — then it should be done when the old man is most vulnerable and most accessible. Some moonless night, on his way home from a party, or on his way to a brothel. No witnesses at that hour, at least none who'd be eager to testify. Gangs roaming the streets. There would be nothing suspicious about such a death. It would be easy to blame it on some passing group of anonymous thugs.'

Cicero leaned forwards in his chair. The machine was reviving. 'So you wouldn't commit the act yourself, by your own hand?'

'Certainly not! I wouldn't even be in Rome. I'd be far to the north in my house in Ameria — having nightmares, probably.'

'You'd hire some assassins to do it for you?'

'Of course.'

'People you knew and trusted?'

'Would I be likely to know such people personally? A hardworking Amerian farmer?' I shrugged. 'More likely I'd be relying on strangers. A gang leader met in a tavern in the Subura. A nameless acquaintance recommended by another acquaintance known to a casual friend…'

'Is that how it's done?' Cicero was genuinely curious. He spoke no longer to the hypothetical parricide, but to Gordianus the Finder. 'They told me that you would actually know a thing or two about this sort of business. They said: "Yes, if you want to get in touch with the kind of men who don't mind getting blood on their hands, Gordianus is one place to start.'"

'They! Whom do you mean, Cicero? Who says that I drink from the same cup with killers?'

He bit his lip, not quite certain how much he wanted to tell me yet. I answered for him. 'I think you mean Hortensius, don't you? Since it was Hortensius who recommended me to you?'

Cicero shot a sharp glance at Tiro, who was suddenly quite awake.

'No, Master, I told him nothing. He guessed it — ' For the first time that day, Tiro sounded to me like a slave. 'Guessed? What do you mean?'

'Deduced would be a better word. Tiro is telling the truth. I know, more or less anyway, what you've called me for. A murder case involving a father and son, both called Sextus Roscius.'

'You guessed that this was my reason for calling on you? But how? I only decided yesterday to take on Roscius as a client.'

I sighed. The curtain sighed. The heat crept up my feet and legs, like water slowly rising in a well. 'Perhaps you should have Tiro explain it to you later. I think it's too hot for me to go through it all again step by step. But I know that Hortensius had the case to begin with, and that you have it now. And I presume that all this talk about hypothetical conspiracies has something to do with the actual murder?'

Cicero looked glum. I think he felt foolish at finding that I had known the true circumstances all along. 'Yes,' he said, 'It's hot. Tiro, you'll bring some refreshment. Some wine, mixed with cool water. Perhaps some fruit. Do you like dried apples, Gordianus?'

Tiro rose from his chair. 'I'll tell Athalena.'

'No, Tiro, fetch it yourself. Take your time.' The order was demeaning, and intentionally so; I could tell by the look of hurt in Tiro's eyes, and by the look in Cicero's as well, heavy-lidded and drooping from something other than the heat. Tiro was unused to being given such menial tasks. And Cicero? One sees it all the time, a master taking out petty frustrations on the slaves around him. The habit becomes so commonplace that they do it without thinking; slaves come to accept it without humiliation or repining, as if it were a god-sent inconvenience, like rainfall on a market day.

Cicero and Tiro were not nearly so advanced along that path. Before Tiro had disappeared pouting from the room, Cicero relented, as much as he could without losing face. 'Tiro!' he called. He waited for the slave to turn. He looked him in the eye. 'Be sure to bring a portion for yourself as well.'

A crueller man would have smiled as he spoke. A lesser man would have cast his eyes to the floor. Cicero did neither, and in that moment I discovered my first glimmering of respect for him.

Tiro departed. For a moment Cicero toyed with a ring on his finger, then turned his attention back to me.

'You were about to tell me something of how one goes about arranging a murder in the streets of Rome. Forgive me if the question is presumptuous. I don't mean to imply that you yourself have ever offended the gods by taking part in such crimes. But they say — Hortensius says — that you happen to know more than a little about these matters. Who, how, and how much…'

I shrugged. 'If a man wants another man murdered, there's nothing so difficult about that. As I said, a word to the right man, a bit of gold passed from hand to hand, and the job is done.'

'But where does one find the right man?'

I had been forgetting how young and inexperienced he was, despite his education and wit. 'It's easier than you might think. For years the gangs have been controlling the streets of Rome after dark, and sometimes even in broad daylight.'

'But the gangs fight each other.'

"The gangs fight anyone who gets in their way.'

'Their crimes are political. They ally themselves with a particular party—'

'They have no politics, except the politics of whatever man hires them. And no loyalty, except the loyalty that money buys. Think, Cicero. Where do the gangs come from? Some of them are spawned right here in Rome, like maggots under a rock — the poor, the children of the poor, their grandchildren and great-grandchildren. Whole dynasties of crime, generations of villains breeding pedigrees of vice. They negotiate with one another like little nations. They intermarry like noble families. And they hire themselves out like mercenaries to whatever politician or general offers the grandest promises.'