The American destroyer escort, the USS Haynes commanded by Robert Mitchum, detects a German U-Boat, commanded by Curt Jürgens, resulting in a prolonged, deadly battle of wits.

Ex con turned private investigator Bradford Galt suspects someone is following him and maybe even trying to kill him. With the assistance of his spunky secretary, Kathleen Stewart, he dives deep into a mystery in search of answers.