Young advertising executive Jim Ferguson suddenly finds himself tossed back and forward in time between present-day New York and the battlefields of World War I. In London he learns that he is the time twin of flying ace Captain James Bigglesworth - `Biggles' to his friends. Unpredictably flung back and forward between eras he comes to the aid of Biggles and his friends as they try to combat a deadly new German sonic weapon...