For 12-year-old Nelly Melcham, it’s hugely embarrassing to be afraid of flying—especially when your mother is the most famous pilot of 1937. So, when her parents make plans for Nelly to fly to Puerto Rico, there’s no way she can say no. Trouble begins for Nelly at a stop in a Miami airport where she gets the surprise of her life in the form of a six-inch tall detective from London named Tim Morcombe. Tim tells her he is on his way to New Orleans on a desperate mission to solve the mystery of a woman abducted by ghosts. At Tim's prodding, Nelly changes plans and together they travel to the jazz-infused, racially segregated city of New Orleans to search for the missing woman. Their only clues to her disappearance? When it rains, her ghost sings sadly from the signpost in front of her house. And a Voodoo priestess has predicted the woman will disappear forever in the next great storm.