Lucia was as good as her word, and she guided them unerringly. Sometimes they went down in the twisting valley bottoms, where fast streams rushed over pebbles worn round and glassy by the ages. At others they switch-backed up scarred slopes to follow narrow paths along the crests. They came to an wide upland plain with a saline lake. The surface of the water was as smooth as marble and alive with shell ducks and avocets. Its beaches were white with the salt, and its rocks also encrusted, as if thick with the droppings of seabirds. Here the villages were more substantial than the isolated hamlets of the heights. The inhabitants were cautious of the armed men, but accepted Persian coins for what produce they could spare. In this region they were able to purchase replacements for two of the horses that had gone lame. Well mounted and fully provisioned, again they climbed, this time to yet higher ranges, where snow lay on the highest summits.

The season was changing. The sun still shone, but with less ferocity. At night in the mountains the temperature plummeted. Some evenings it rained, and afterwards the air brought the tang of autumn. Valens had lost track of time. He thought it was towards the end of September. As they had gone on, somehow the customary man-made divisions of time – the days and the months – had lost their hold. They had been replaced by the endlessly repeated routine of the march: the four watches of the night, first light and seeing to the horses, feeding themselves, breaking camp, setting out at a walk, then a trot, the first halt to check the girths and relieve themselves, all the way through to making camp again, bedding down the horses, eating their rations, and falling into their bedrolls.

Lucia fitted into the routine. None of the men bothered or importuned her. They seemed, if anything, to have adopted her as something between a cherished pet or a mascot. And, of course, they all knew that without her they would be lost.

Once, not long after the killing, Valens had asked her what she intended to do. She had replied that if the gods did not provide, she was not without resource. The future had not been discussed again on the journey.

Finally, she led them to a river running east. At first it was fast and shallow. Descending, it gathered volume from smaller streams. The rock walls fell back, and it meandered, wide and deep, through a green valley of its own making. Isolated tall outcrops of banded rock testified to its power and its changes of course over time.

When the wind was in the east, it brought the smell of the sea.

Then they came to the bridge.