April 1928: Daisy Dalrymple Fletcher is visited in London by her young cousins, who are eager to see the Crystal Palace. Yet this ordinary outing goes wrong when their nanny Mrs. Gilpin goes off to the ladies' room and fails to return. When Daisy goes to look for her, she stumbles upon the body of another woman dressed in a nanny's uniform. After spotting Gilpin chasing yet another nanny, Daisy later finds her unconscious and unable to remember what she was doing. Daisy's 23rd case (after Superfluous Women) is perhaps her strangest, as she will need to discover the identity of the third nanny—the presumed murderer—and figure out what in the world is going on with Mrs. Gilpin.