In 1915, Captain Liers, commander of a submarine is leaving his hometown, where he, his 2nd officer and the radio-operator, spend their shore leave. On patrol they sink a British armored cruiser, but while returning to their harbor, they’re attacked. They’re able to sink it, but the trap has alarmed a destroyer, that sinks their sub. The sub lays on the sea bed at 200 feet, and except for the bridge, it is full of water. 10 members of the crew survived, but there are only 8 rescue devices.