While investigating a murder case, a detective stumbles upon a rare-stamp swindle involving the victim's twin sister.

British agent Bulldog Drummond is assigned to stop a master criminal who uses beautiful women to do his killings.

A series of unexplainable accidents befall the people and companies responsible for developing the world's first supersonic airliner. A British agent is sent to investigate and with the help of another agent uncovers a plot masterminded by Carl Petersen who stands to gain eight million pounds if the aircraft is not ready by a certain date.