What's a holiday without surprises? It's Christmas 1867 at Underbyrne, the Holmes family estate. The house is filled with family, relatives, and three unexpected arrivals-all ready to celebrate the holidays. That is, until another uninvited guest appears: dead in the stables. The discovery marks the beginning of a series of bizarre occurrences: Sherlock's young cousin reports hearing footsteps outside the nursery, Mycroft suddenly falls head-over-heels in love, and the family learns more than one person under their roof harbors secrets. Is someone in the household a murderer? Sherlock must discover the dead man's identity before another un-welcomed body materializes.