Young Cass has invited her friend Kelley Branscombe over, but things begin to take a turn when her annoying little brother, Brion, unearth's an old flag stone.
Cass convinces her mom and dad to let Kelley stay the night. But there is one rule: Cassandra can't invite her boyfriend, Eric Pearlman, over. Meanwhile, Brion is insisting he is seeing some kind of shadow or strange man. Cass denies seeing it.
Who else shows up to the Thompsons' house for a sleepover? Who has never left?