In early 1945 the Nazi submarine U-745 is lost and the body of its captain is found frozen on the island of Foglo. For nearly seventy years the U-boat's fate has remained a mystery. Now after over a decade of painstaking research and underwater exploration the mystery of the U-745 has been solved by the members of Badewanne, a Finnish diving team. While searching, they dispel the myth of the Louhi, a Finnish minelayer that some thought was sunk by its own mine and discover a type of submarine some say was never built. This group of highly skilled technical divers take the viewer on a journey deep below the frigid waters of the Baltic to reveal the secrets of the "NAZI SUNKEN SUB."