Film noir takes a paranoid ocean cruise. When heiress Jeanne Crain's newlywed husband disappears on their honeymoon aboard a luxury liner she looks fore and aft in this mystery suspenser. Seems no one saw him embark...is she slightly mad? Or is it a nefarious plot? The ship's kindly doctor (Michael Rennie) can't figure it out nor will you 'til the dizzy denouement on the promenade deck.