挪威的一次冬季潜水之旅变成了两姐妹的惊魂之旅，在潜水过程中其中一人被落石困在了海底，此时必须与时间赛跑，因为氧气在悄悄的流失。A winter diving trip in Norway turns into a desperate race against time for two sisters when one of them becomes trapped at the bottom of the ocean by falling rocks.
