This amusing and briskly moving adventure centers on a jewelry heist, though the actual "Bulldog Drummond" has a limited role. He’s caught up in an automobile incident, and fortunately, the courageous – although not particularly helpful – “Pennington” (Jack Hulbert) volunteers to assist a woman in need, who is called “Ann” (Fay Wray). Her predicament arises because her grandfather, a skilled necklace maker, has been taken by criminals planning to produce a fake replica of a piece they intend to steal from the British Museum. The pair then find themselves on a risky quest through the tunnels beneath London, trying to locate the secret base of the would-be thieves and recover her missing relative while also attempting to foil the schemes of their detached and shrewd adversary. It isn’t long before we realize who this villain is, largely because of his prominence in the film, but that doesn't detract from the excitement, and the finale involves a genuinely thrilling display of both camera work and performance. Admittedly, it does move slowly at first, but once it gains momentum, it becomes a rather enjoyable movie that easily exceeds 75 minutes in length.

Source on TMDB