After a long winter trapped in the ice, scouting parties are sent out in search of open water. One of the teams makes a frightening discovery.

With something now stalking the ships, the captains debate their options, testing their loyalty to one another against their duty to their crews.

A cunning attack on the ships proves the men are not battling an ordinary bear and that the region's Inuit culture may hold a key to their survival.

A strange illness begins to show itself while another more familiar one jeopardizes the expedition's most valuable resource - its captain's judgment.

With the end of their provisions in sight, officers contemplate an 800-mile walkout while planning a party to raise the men's worsening spirits.