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.
Far from land, Arthur Wilde and his team of scientists celebrate the culmination of decades of research: a solution to climate change. Then, a gruesome murder – eerily similar to Wilde’s South Pole nightmare – occurs onboard.
Zach goes missing before he can release the DNA results from Kowalski’s murder. Yuto brings Wilde the surprising results of his web search. Olivia escalates her search for the famous scientist.
With Charlie locked up, Amy brings lingering doubts to Wilde, confirming his greatest fears. In the U.K., Olivia and her sister are attacked while plotting their revenge.
After breaking out of his confinement, Charlie cuts the ship’s power once again and embarks on a murderous rampage. As Olivia finds herself one step closer to Rachel, Gloria pulls away from Wilde.
After another scientist turns up dead, the mole reveals their true identity – and asks for a favor in return.
As the Alexandria threatens to explode, the remaining scientists jump ship and onto the only life boat – putting them face-to-face with the real killer.
