Film star Didi Druson receives a number of mysterious threats telling her she will "never see twenty-five". Although he suspects a publicity stunt, Garnett agrees to fly to Vienna with her on the eve of her twenty-fifth birthday.

A sick man, suffering from loss of memory, is identified as the wealthy Ian Denning, believed lost in the South American jungle three years before. But his wife does not recognize him - is he an imposter?