Pressing south, they passed village after village in a landscape dense with farms, most abandoned. The towns here were built of stone, the streets set out to rigid grid patterns. This far south they were entering territory that had once come under the sway of Carthage itself, whose imperial holdings had waxed and waned with the centuries, but whose influence lingered in the older building stock.

Then, one morning, they woke to a smell of smoke.

Emerging from her tent, Rina saw an orange-grey smudge across the southern sky: a forest fire, and a big one, right across the horizon. They had no road to follow save the track that followed the river, no choice but to go on and challenge the fire, to walk right through it.

In the worst of it, it seemed as if the whole land around them was ablaze. The terrified horses had to be led by hand, and the people wore moistened cloth over their faces. There were firebreaks around some of the villages, but others had been abandoned to the flames. Nestspills cluttered the road, people walking alone, families – everybody heading south, ever south. There was no sign that anybody was seriously trying to challenge the fire.

‘They’ve had drought here,’ Alxa said to her mother, shouting through her mask and the noisy crackle of the flames. ‘That’s what Pyxeas told me. Worse than in the north. He said we had to expect this. The trees dry out until the slightest spark hits, a lightning strike, and the whole landscape goes up in flames.’

‘Trees grow back,’ said Rina.

‘Pyxeas said it may never be the same. The trees that grew here before may not prosper in the conditions to come – colder, dryer, windier. Maybe pine trees will grow here next, not oaks and ash.’

‘This far south? Surely not.’

‘That’s what Pyxeas says.’

It must, Rina thought, be terrifying to live inside Pyxeas’ head. To predict such an appalling sight as this world on fire, and to understand.

It took two days to walk through the tremendous fires, and several further days’ travel along increasingly crowded roads, before they came to Massalia.

The city was a sprawling port with a fine natural harbour and a broad estuary. Here, Barmocar boasted, in this Carthaginian dependency, after a long trek through countries of savages, he was sure of a civilised welcome.

Rina could see there was trouble here even before they came into the city itself. Beyond the harbour, on the broad face of the Middle Sea, she saw ships standing out to sea, apparently motionless. Had they been refused permission to come into the harbour? And on land, as they neared the city, the road was packed with nestspills, the fleeing folk evidently so fearful of plague they kept their distance from their neighbours and wore masks over their faces. It was a whole countryside, Rina saw, draining south towards Massalia.