In the most inhospitable environment - cut off from the rest of the world - there's a killer on the loose. A&E doctor Kate North has been knocked out of her orbit by a personal tragedy. So when she's offered the opportunity to be an emergency replacement at the UN research station in Antarctica, she jumps at the chance. The previous doctor, Jean-Luc, died in a tragic accident while out on the ice. The move seems an ideal solution for Kate: no one knows about her past; no one is checking up on her. But as total darkness descends for the winter, she begins to suspect that Jean-Luc's death wasn't accidental at all. And the more questions she asks, the more dangerous it becomes . . .