A look at the lives of the officers and men of the U-96, a German U-boat patrolling the north Atlantic during World War II. Led by Capt.-Lt. Heinrich Lehmann-Willenbrock, the men, for the most part, are seasoned veterans of undersea duty. For the new recruits, including military journalist Lt. Werner, it's all a bit of an eye opener. The quarters are cramped with men sharing bunks - while one is on duty, the other gets sleep - and there's barely enough room for more that two men in passageways at any one time. Their trip is also marked by lengthy periods of boredom while they search for enemy shipping to attack and periods of absolute terror when they find themselves under attack by Allied naval vessels. Throughout it all, the men band together, cynical about just what they are doing but also proud of their accomplishments.