In 1921, four men ventured into the Arctic for a top-secret expedition: an attempt to claim uninhabited Wrangel Island in northern Siberia for Great Britain. With the men was a young Inuit woman named Ada Blackjack, who had signed on as cook and seamstress to earn money to care for her sick son. Conditions soon turned dire for the team when they were unable to kill enough game to survive. Three of the men tried to cross the frozen Chukchi Sea for help but were never seen again, leaving Ada with one remaining team member who soon died of scurvy. Determined to be reunited with her son, Ada...