A gripping espionage thriller, which sees two spies locked in a psychological battle of wills in the run up to the Second World War. A fire rages across the decks of the superliner Normandie, interned in New York harbour and being converted into a warship for World War II. As the burning ship sinks, it becomes clear that a Nazi spy is behind the disaster. And naval architect Steven Gates must expose the agent's deadly plans for even greater destruction. Soon the two spies are locked in a psychological battle of wills that takes them deep into the Normandie's sunken hull - and almost costs Gates the love of the only woman who can save him.