We did keep searching as long as it was feasible. Several more days passed, but we lost heart now we were walking and carrying all our kit. We still had our mules, though once we lost Nero, Corex and Basiliscus had odd looks in their eyes as if they wished they had bolted; Corex had never been a group player anyway. We had to abandon the cart, another expensive loss for the Petronius brothers. Our task came to seem pointless. Nothing that bore any relation to a crime scene turned up. Looking for corpses in that sodden, scratchy, empty area was hopeless. The marshes were endless, horrible, ominous. Without a definite lead, we could wear ourselves out until the flies and disease finished us, yet achieve nothing. Depressed beyond bearing, we took a vote and agreed to give up. We had done our best. We had done more than anybody else had ever bothered to do.

The trip back took a long time and the first stage, heading back to Satricum, made us more sore-hearted than anything. When, still humping our packs, we passed the shack where Claudius Probus lived, he sniggered openly. He blamed the ox theft on the bandits who were supposed to have colonised the marshes. Curiously, we never saw any sign of such bandits. My guess was that the Claudii had seen off all the competition in these parts years ago. Most bandits are cowards, who avoid serious confrontation.

When we reached the good road and collapsed at the Satricum inn, the landlord expressed great surprise to see us. However, he was eager to hire us extra mounts, and very conveniently had some donkeys available; the two vigiles went with him to inspect them. Petronius sat set-faced, glaring as if he now thought the landlord was responsible for our loss of Nero.

Helena’s brother Justinus went indoors to talk to the waitress, Januaria; neither Petro nor I had the heart. He returned looking thoughtful. ‘She was talking about foreigners—that’s anyone they don’t count as local, I suppose. Some foreigners who take a road through the marshes don’t come back; well, not this way.’

‘That is because they have had their transport stolen!’ Petro snarled.

Quintus and I exchanged glances. If the girl had made him think what she said was significant, I trusted him.

Petronius continued to resist. ‘You head south, because you’re going south. When you get there, that’s where you want to be. So you stay there. In the south.’

‘Logical,’ I cracked. ‘For simpletons!’ I was feeling tetchy myself.

He carried on ranting. ‘It follows that miserable inn-folk to the north don’t see you again. They won’t see me again either, once I get back to Rome.’ Petro took a swig of wine from his beaker, spat, slammed down the cup in high disgust, then strode out, shouting to us all to move. He had had enough of the countryside. He was going home.