In the middle of the winter, a small group of scientists in charge of an international base in the Antartica during the long polar nights stops communicating with the outside world.

The summer team tries to find clues of what could have happened during the winter, unveiling a first possible suspect.

As Maggie begins to recount details of how the members of the team were killed, the search team discovers a frozen hand peeking out from the snow near the base.

Arthur reveals that the body found by the team was that of Sarah Jackson's. Meanwhile, Maggie discloses that Sarah's death was not an accident. She was murdered.

The survivors head to the burnt out station of Polaris V hoping to salvage communications equipment. But the mystery deepens. Did the death of a Polaris V scientist lead to the events of today?

Johan realises they've been searching in the wrong direction all along. He urgently redirects the search for his missing wife, which can resume after the storm has finally passed.