John Blake, an international jewel thief who died in a plane crash, leaves in his will a mysterious package to a barmaid to be given to her ten years after his death. In his instructions to his attorney, Harwood, he asks that not only the barmaid, Rosie Holland (known as 'The Duchess')' be present but also Colonel March. Blake and March knew each other and Blake thus knew of March's fondness for puzzles. As a frequenter of the pub where she worked, Blake only casually knew the Duchess but left her a gift as a token of his appreciation for her kindness. The gift turns out to be a worthless music box that plays the tune 'The Twelve days of Christmas.' The attorney is attacked and just before dying tells March and Ames that the attacker was after the supposed contents of the box - but there was nothing in the box . . .
Madame Richter, a con artist spiritualist come to see March with an odd story. He greets her with saying "My old fortune telling friend. People go to fortune tellers for one of two reasons - hope or fear." Madame Richter then tells him that one of her clients, Mrs. Fortesque, wanted to communicate with her dead son. But then during a séance the fake apparition didn't appear but a real one did! At the home of Mrs. Fortesque, Madame Richter shows March how her fake séance worked but he already knew many of the tricks of how phony spiritualism worked. Colonel March later participates in a séance and again strange happenings occur - including a murder . . .
