I though this had a little of "The Lady Vanishes" (1938) to it as we follow the adventures of "Ruth" (Jeanne Crain) aboard a cruise liner. She embarked with her new husband "John" but he's gone missing. Not just missing, but there's not a trace of him to be found anywhere. The Captain (Willis Bouchey) and ship's doctor "Manning" (Michael Rennie) are not convinced that she's the full shilling - and as she becomes more and more frantic and desperate most conclude that the man never existed in the first place! Gradually, though, we realise that this is quite a clever cat and mouse game with a man...