A romantic prison musical, concerning a dancer working in a sleazy Marseilles portside bar, which is really the front for a bordello. While dancing one night, she meets a sailor and agrees to be his bride. Unfortunately, one of her former suitors suddenly shows up and a terrible fight ensues. The sailor kills his rival and ends up sentenced to Devil's Island. The only women allowed there are the wives of the guards, so, not wanting to be far from her beloved, the dancer marries the meanest guard in the prison. During a prison riot, the sailor proves his mettle and gets pardoned. The couple happily decide to return to the dancer's native Britain.