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'.

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'.