A German submarine hunts allied ships during the Second World War, but it soon becomes the hunted. The crew tries to survive below the surface, while stretching both the boat and themselves to their limits.

At the start of World War II, Cmdr. Ericson is assigned to convoy escort HMS Compass Rose with inexperienced officers and men just out of training. The winter seas make life miserable enough, but the men must also harden themselves to rescuing survivors of U-Boat attacks, while seldom able to strike back. Traumatic events afloat and ashore create a warm bond between the skipper and his first officer

The crew of the American destroyer escort, the USS Haynes, detects a German U-Boat—resulting in a prolonged, deadly battle of wits.

The story of a Canadian WWII naval vessel, with a dramatic subplot concerning her first captain.

A view from Canada of the North Atlantic convoy route during the Battle of the Atlantic, presented in the framework of the turnaround of a single convoy at Halifax, Nova Scotia.

Germany in 1941. War in Europe for two years. The Nazis at the height of their power. Since the beginning of the war, there has been a frontline in the west where the traces of horrible fights disappear on the spot:The Battle of the Atlantic. England, traditionally the leading naval power worldwide was to be cut off from all supplies by a blockade while the balance of power is not in favor of the German Kriegsmarine. Their commander-in-chief complains that "the war was five years early." That a victory seems achievable at the beginning is the result of a weapon that was only known in Germany at the height of perfection and drill: submarines.