In 1939, a group of skiers set off on a five-day ski trip in the Lapland mountains. Due to a severe storm, they are snowed-in a mountain cabin. On the first night, a murder takes place, the successful businessman Weismann is brutally stabbed to death. The group's participants realize, horrified, that the killer must be one of them. In order to endure the following days trapped in the cabin, they must try to solve the murder mystery themselves.