While on his way to London to meet with a mysterious lady, Bulldog Drummond (Atholl Fleming) is injured in a car crash after unscrupulous criminals tamper with his car. He enlists the help of the guy whom he crashed into, Jack (Jack Hulbert), to impersonate him and listen to what the woman who is waiting for Drummond has to say. Jack relishes the chance for some excitement, well until there actually is some excitement then he isn't that keen...
His adventures, along with Algy (Claude Hulbert), take him into a plot by Morelle (Ralph Richardson) to copy stolen jewels after kidnapping the grandfather of Ann (Fay Wray). After much flapping about and sometimes aimless escapades everyone finds themselves on board a stolen tube train being driven at speed seemingly to it's doom!
It is all played very light, unfortunately this can make the film a bit unbearable at times as it approaches (and roars past) self-parody. However, the film flies along at such a speed that dull or awkward bits do not last very long. A fun fact with this film is that the villain (Richardson) actually plays Bulldog Drummond in the previous year's The Return of Bulldog Drummond! Algy is played by Jack's real-life brother.
The view of the 1930s London Underground is very interesting, including scenes from the (then) recently closed British Museum station.
