While they rested in the shade of a rock shelf at noon, they heard the song of a bear twisting up from the trees far below. Impossible to tell if it was Seven or one of the feral bears native to the country: they had left behind the territories of those Trina had tagged. She put up several bots, but the song’s last cadence had fallen away before she could track down the singer.

That night they made camp in one of the little meadows, and as before lit and tended a fire through the night, but if anyone saw it they kept away and there was no sign of any other fire in all the dark land.

In the morning Ysbel and Trina buried the ashes of their fire and packed up camp and went on, walking above an ocean of fog that flooded the contours of forest slopes far below, filling valleys and washing against high ridges and throwing up columns of vapour like the towers of a phantasmagorical city reaching into a sky so clean and blue and empty the world might have been created with the dawn, or time might have been wound back to an antediluvian age before the Burn Line, before the ancestors of the first hominins had crept out of the forests of Africa and lit their first fires and chipped stones into the first tools.

The sun burned away the fog and warmed the high country, and by noon the two women had taken off their jackets and hooked them to their packs. Ysbel tied the sleeves of an undershirt around her head and draped it over her neck and shoulders; Trina, already baked by days of ocean weather, went bareheaded, eagerly forging ahead. Late in the afternoon, they reached the end of the ridge they had been following and saw beneath them, at the bottom of a steep-sided hanging valley, an eye of emerald-green water ringed by a belt of dwarf birches and balsam firs.

‘This is the place,’ Trina said. ‘This is Raia’s lake.’ She called out her partner’s name, and it echoed off the stony slopes and startled up several small birds from the trees, but no one answered.