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 deserted airfield - a plane with stolen gold - and in the hut the tea is still warm in the teapot. This is the mystery Delaney has to solve when he flies to the emergency landing strip in the African bush.

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?