Shirou is climbing a mountain when he gets caught in a severe blizzard and takes shelter in a nearby shack. The blizzard worsens, and Shirou braces himself to wait it out. But soon, disturbing sounds fill the shack, bringing terror he never expected.

A pair of college girls have climbed to the top of the mountain. Out of boredom, one of them, Eriko shouts loud to hear her own echoes.