At the height of Hitler's infamous U-boat war, the crew of the U.S.S. Swordfish were heading home after months at sea. They never made it. Now prisoners of war aboard U-boat 429, a small group of American survivors will find their loyalties put to the ultimate test when they're forced to join their German captors to fight for their very lives.
During World War II, Captain Cassidy and his crew of submariners are ordered into Tokyo Bay on a secret mission. They are to gather information in advance of the planned bombing of Tokyo. Along the way, the crew learn about each other as they face the enemy and some of them lose their lives.
In the midst of World War II, the battle under the sea rages and the Nazis have the upper hand as the Allies are unable to crack their war codes. However, after a wrecked U-boat sends out an SOS signal, the Allies realise this is their chance to seize the 'enigma coding machine'.