Twin sisters Hanna and Alex, who together run the Murder and Mayhem book and chocolate shop, find their volunteer work at their local Christmastime high school reunion event turn serious when they discover an old classmate's dead body. That classmate, it turns out, had been hitting on Hanna only hours before, and, worse, was killed by a nutcracker figure the sisters had been admiring at the party. Now, Hanna is a prime suspect in a murder case, and only Alex and their sleuthing canine companion, Watson, can clear her name and find the real killer.