One Mysterious Night.

The Blue Star of the Nile is stolen from an exhibition guarded by the police under Inspector Farraday. Boston Blackie is certain the robbers had inside help. He finds a wad of gum under some of the furniture at the exhibit hall; it still bears the impression of the diamond. Blackie targets George Daley, the assistant manager, especially after he learns that George had recently bought a large amount of gum. Daley's sister Eileen finds out that her brother is involved with thieves Paul Martens and Matt Healy.