While the air up there was so cold it glittered like finely ground diamonds, a little piece of hell bubbled away just below the surface. Acid in the ground turned trees into tinder. It burned the grass off the land, making the soil scab with wet copper pools like freshly scalped skulls. Only raised boardwalks kept Yellowstone’s inhabitants safe. They crisscrossed the park, stopping a sturdy boot from breaking through the Earth’s thin crust while a series of little wooden stepping stones and moveable walkways broke the path from one cabin to the next, keeping the Dead from every door.

Yellowstone had a volcano deep in its heart, and its broiling skin was the deadliest of all the park’s natural defences. And yet, when the great geysers burst, rousing plumes of hot water and chattering goshawks up into those roaming skies, this place was damned near perfect. Crying shame then, that this life beneath the doming blue was all but coming to an end.

Wyatt lifted the pan from the blue flame, swilling dregs of fizzing coffee round the rim, and watched the snow dance across the cabin window. He yawned. He scratched his butt. He considered taking a piss in the sink while Daisy was still asleep just so he didn’t have to use the outhouse. He thought again. He poured the pan, taking brief pleasure in the sting of heat curling up from the enamel cups and threw another log on the fire. It popped, or maybe one of the mud pools beneath the cabin did – who could be sure at this godforsaken hour? – and he stood up on tiptoe to peek above the snow shelving the sill.

Outside, steam chugging up from the geysers broke through cracks in the decking. It was so thick this morning, it smothered the air like September snow over summer dreams. There was no sight of the surrounding boardwalks and cabins. They may as well have been up in the clouds. Only the low winter sun was visible, glowing dully inside the mist like a moon. That and the little wooden bridge reaching out from the cabin to greet it.