A scientist is nearly assassinated. In order to save him, a submarine is shrunken to microscopic size and injected into his blood stream with a small crew. Problems arise almost as soon as they enter the bloodstream.
A civilian diving team is enlisted to search for a lost nuclear submarine and face danger while encountering an alien aquatic species.
In November 1984, the Soviet Union's best submarine captain in their newest sub violates orders and heads for the USA. Is he trying to defect or to start a war?
A German submarine is boarded by disguised American submariners trying to capture their Enigma cipher machine.