Follows the sordid relationship between a stepfather, Atsuki, and his two adolescent stepdaughters, Airi and Marina. The young girls' mother is absent for the most part of the story, presumably due to work, allowing for her new husband to pursue his dirty pleasures in peace.
The family holiday didn't quite live up to Airi Akizuki's expectations. Her stepfather, Kouzou Akizuki, decided to take her on a weekend trip to a ski resort—after all, nothing brings a family closer than shedding some sweat under the crisp winter sky.
However, as it soon turns out, Airi is not the most skillful skier out there. Moreover, as the wind picks up and a snowstorm looms on the horizon, the pair finds themselves trapped in a chilly cavern. They are losing heat at a frightening pace, but there is one activity that will keep them warm for sure.