A plane crashed onto the endless snowfields of Russia. Guest, who lost consciousness at death's door, wakes up in an unfamiliar cabin filled with the sound of crackling firewood. The bandages wrapped around her body and the pungent smell of disinfectant stinging her nose serve as a grim reminder of the accident.

The woman treating Guest's wounds is Ekaterina. A former GRU agent, she checks Guest's pulse with a cold expression. It remains a mystery why she, a woman extremely wary of outsiders, saved Guest, and when they will ever be able to escape this isolated snowy mountain.