Sixteen-year-old Peter Rogers is training to be a Royal Navy officer in 1939 when he hears that his father's ship has been torpedoed off the coast of Ireland. The survivors, including his father, have been captured by a German U-boat crew and treated cruelly - some of them are shot dead. In 1940 Peter joins an escort fleet in the North Atlantic where British convoys are suffering horrific losses from enemy U-boats. We share in the trials and tribulations of his duties, including the constant tension, the bitter cold, mountainous seas - and the moment when he and his father's captor come face to face...