It's been a long, hard winter in the small Alaskan town of Lake's Edge - and things are about to get even tougher. Lisa McCall, a young and brilliant research scientist, has disappeared out in the wilderness in the middle of a snowstorm. Lisa's sister, Abby - shaken by the news - flies out from England to join the rescue team. Abby and Lisa have been estranged for years, driven apart by a terrible row, both believing there would be time in the future for forgiveness. Now Abby must face up to the fact that her sister may be gone forever. As soon as she arrives at the freezing outpost, Abby knows there's something wrong. Lisa's cabin has been ransacked and her research material is nowhere to be found. It emerges that Lisa was on the verge of patenting an incredible discovery - facing fierce opposition from the oil-dominated energy market. Abby begins to see that Lisa's work has threatened some very powerful people - who are willing to stop at nothing to protect their interests. Abby knows her sister is out there somewhere, battling deep cold and raw terror, while her enemies circle. After so many years of brooding silences and explosive rows, Abby is forced to face up to the past, while her younger sister fights for a future. Risking her own life, she embarks on the dangerous task of locating Lisa before someone else gets to her first.