It's Christmastime, and the precocious Flavia de Luce--an 11-year-old sleuth with a passion for chemistry and a penchant for crime-solving--is tucked away in her laboratory, whipping up a concoction to ensnare Saint Nick. But she is soon distracted when a film crew arrives at Buckshaw, the de Luces' decaying English estate, to shoot a movie starring the famed Phyllis Wyvern.