 The film depicts the story of Benedict Hisston (Lugosi), who is part of a plot to destroy the Panama Canal.Initially unable to obtain necessarily intelligence from Richard Decatur (Lowe), a captain in the United States Navy, he enlists the aid of femme fatale Peg Williams (Mansfield).Decatur pretends to be seduced into the conspiracy, costing him his career and estranging him from his wife (Tell), but he ultimately betrays the saboteurs in Panama and stops their plan.