The Unicorn Club is throwing the best Halloween party Sweet Valley Middle School has ever seen. Lila's dad has lent the girls a run-down shack in the woods, but when they start to fix it up, spooky things begin to happen.
While in Scotland visiting relatives, thirteen-year-old twins hunting for ghosts in an old cemetery find big trouble when Peter is possessed by the spirit of a man who is determined to keep his twin sister from the man she loves.
Lee, certain that the Halloween ghost that visits her family is just a trick played by her mother or father, decides one year to go outside and dance with Hubknuckles the ghost.