Behind the public galleries of London's Natural History Museum lies a set of stranger, grimmer stories, and this film goes through the storerooms and archives to tell them. Curators pull out 15,000-year-old bones from Cheddar Gorge that carry cut marks consistent with cannibalism, and researchers walk through the wartime work of the SOE, whose scientists rigged dead rats with explosives to smuggle into German factories as sabotage devices. The museum's collections also hold the Delhi Purple Sapphire, a gemstone whose owners reported run after run of bad luck after taking it home, and specimens tied to the extinction of the dodo and the disappearance of the Barbary lion from the wild. Curators and researchers narrate each object on camera, moving between display cases and back-of-house collections most visitors never see. The film treats the museum less as a hall of stuffed animals than as a repository of unresolved cases, each one traced back through the specimen that first recorded it.