"Wheels within wheels," muttered Eco.

"Better than one great wheel driving the whole engine of the world, which is what some people would like to see," said Cicero. "But I'm pressed for time. Caesar will be leaving Ravenna any day now, heading back into the field. There are rumours of a new uprising led by some Gaul with a typically unpronounceable name. What is it, Tiro?"

"Vercingetorix," said Tiro crisply. He was clearly not inebriated.

"Whatever," agreed Cicero. "So you see, I have no time to go off looking for – what did you call it, Eco? 'A disused stable in a derelict field.' And neither should you, Gordianus. Don't tempt the Fates. You're safe in my company. I'll provide all your needs. Accompany me to Ravenna tomorrow, and then accompany me back to Rome."

"We should head back to Rome at once," said Eco glumly. "For Bethesda and Menenia to suffer even one more day than they should, not knowing what's become of us -"

"Ah, but don't you have a brother who's likely to be with Caesar in Ravenna?" said Cicero. "Yes, your son, Gordianus – the one called Meto. Your family will have written to him about your disappearance, I'm sure. He'll be as distraught as they are. This is your chance to see him before he heads back north with Caesar. You see, you must come with me to Ravenna. But now, I think it's time for everyone to retire. You look weary, Gordianus, and Eco is yawning. Tonight, you'll have the best accommodations our host has to offer, with a soft bed in a private room. I arranged it for you myself I predict that you will sleep like stones."

And we did.

Caesar's residence in Ravenna was a large villa on the outskirts of the city, with numerous tents, stables and makeshift buildings set up around it. Like all military camps, it resembled a small city, where the needs of a vigorous, mostly young male population with strong appetites could be accommodated on a daily basis. One invariably encounters three things in such places: the sight of prostitutes, the constant smell of cooking, and the sounds of the crudest language imaginable.

We arrived shortly after midday. Cicero and Tiro went to seek an audience with Caesar. Eco and I went in search of Meto. He was not hard to find. A foot soldier pointed the way to a tent filled with young officers. As we stepped inside, there was a sudden hush which had nothing to do with us, followed by a rattling noise, then an outburst of raucous laughter and cursing. They were playing dice.

The four dice being used were an old-fashioned set made of bones, pointed at two ends with the numerals painted on the four flat sides. A young man stepped out of the crowd and leaned forwards to scoop them up, and I saw with a catch in my throat that it was Meto.

Since he had begun his career with Caesar, we had seen each other only a few times a year at most, and never for long enough. Each time I saw my younger son I braced myself for an unpleasant surprise – a limp, a digit missing, a fresh scar across his face to add to the faded one he received in his first battle. So far he had kept himself intact, if not unmarked. Each time I saw him I was struck anew by how young he still looked. He was twenty-six now, very much a man by every measure, with a few grey hairs at his temples already and a ruggedness to his features that comes from years of hot sun and cold wind, but when he smiled as he scooped up the dice

I could not help but see the child I had redeemed from slavery and adopted twenty years ago. He had always been a good-natured boy, affectionate, laughing, mischievous but even-tempered. It was hard to imagine him killing strangers for a living.

Meto became a soldier at the age of sixteen when he ran off to fight for Catilina. In the battle of Pistoria he gained the scar across his face that he was still so proud of I had thought – hoped – that would be the end of a youthful folly, but Meto still sought the thing he had found with Catilina. He found it again in Caesar. And Caesar, fortunately, had found Meto, discovering his talent for words and taking him into his private service as a sort of literary adjutant. (Caesar the politician was always busy writing and publishing the memoirs of Caesar the general, and commanded his own private troop of wordsmiths.) In recent years Meto had also found service as a translator, having shown an aptitude for learning the Gaulish dialects. In addition to these sedentary pursuits, he still saw plenty of battle and danger, often at the side of the great general himself. I could never stop worrying about him.

He had not yet seen us across the crowded tent. As he rattled the four dice in a cup, he narrowed his eyes and seemed to mutter an invocation – to a god, to a lover? Who were his gods these days? Who were his lovers? We never talked of such things any more. He gave the cup a final shake and let fly the dice.

A hush, the rattle of bones, then more laughter and curses. Meto himself was loudest of all, raising his arms triumphantly in the air as he laughingly announced, "The Venus Throw! One of each number-the Venus Throw beats all! Pay up, pay up!" The long sleeves of his tunic slid down his upraised arms and I noticed a new scar, red and gnarled, which cut across the biceps of his left arm. It was ugly, but seemed to cause him no awkwardness or pain. He reached into his tunic for a little bag and opened it wide for the others to throw coins into.

Then he saw Eco and me.

I think I knew then how my own face must have looked, on those occasions when I had been separated from him by great distances, and had worried for him, not knowing if he was alive or dead, and then at last had seen him again, often by surprise when he appeared in Rome without announcement. It was the look of a man whose eyes discern in an instant what his heart has spent long hours desiring.

"Doesn't your commander object to your gambling?" I said.

"Not as long as we wager only with coins that have his image on them." Meto laughed at his own joke. Roman coins do not bear the images of living men, only dead ones. Not even Caesar dared to mint a coin with his own portrait.

We had retired to a quieter place, a tiny room in the villa that was crammed with scrolls, parchments and maps. There was barely room for the three of us. This was the place where Meto did much of his work for Caesar, reading and emending his latest volume of memoirs. Deciding on a consistent spelling of Gaulish names was an ongoing crisis, I gathered.

I asked him how he knew that Eco and I had been missing.

"Diana sent a letter. It's a good thing you taught her to write, you see? Though her syntax is atrocious. You really should spend more time drilling her, Papa, or else hire a decent tutor. I could tell she was very upset. Her hand shook. Here, I'll show you." He shuffled among a pile of documents and retrieved a slender, folded wooden tablet. I untied the ribbon that held it shut. The letters etched into the wax coating on the inner surface were indeed uncertain and wavering.

Brother,

We are in great worry and sadness here. Papa left on a journey of a few days and on the way back they were attacked and carried off him and Eco.

There is maybe cause for hope. There was a note give to the guard outside the door early this morning, by a man who hid his face. The note was addressed to Mother, but of course I had to read it for her. It says: "Do not fear for Gordianus and his son. They have not been harmed. They will be returned to you in time." But who knows who the note is from? Or whether to believe it? It makes me more worried than before, almost.

The city is not as wild as it was, but still dangerous, especially at night. Mother and me, and Menenia and Titus and Titania are all safe. We have plenty of the great man's guards to keep us safe. Don't worry for us. But I long for Papa and Eco to come home! Oh, Cybele, let them come back soon!