Ever since the tragic death of his beloved wife, Jean (KATHRYN ANDERSON), Arthur Kriticos (TONY SHALHOUB) is a widower who's just been trying to get by and raise his kids, Kathy (SHANNON ELIZABETH) and Bobby (ALEC ROBERTS), with the aid of Maggie (RAH DIGGA), the nanny. Thus, when attorney Ben Moss (JR BOURNE) arrives at his door and informs him that he's inherited the mansion of his now late Uncle Cyrus (F. MURRAY ABRAHAM), Arthur can't believe his luck.
Nor can he or the rest of the family believe the immense abode, comprised almost entirely of glass walls with Latin phrases on them. Upon their arrival to look around the place, they also meet Dennis Rafkin (MATTHEW LILLARD) who claims to work for the power company, but in reality is a psychic who worked with Cyrus in capturing ghosts that are now stored in the mansion's basement.
It seems that Cyrus had copied ancient plans and built a machine designed by the Devil and powered by the dead that would give him ultimate power. Once the twelve ghosts of the Black Zodiac were assembled, their spirits would fuel the machine and start the process of unleashing that power.
Although Arthur and the others don't believe any of the ghost stories, after a few encounters and visions of them through special glasses that allow one to see the menacing spirits, they do. Unfortunately, the mansion, which keeps changing shape due to the machine opening and closing doors and hallways, is now locked and Kathy and Bobby are missing.
From that point on, and with the help of ghost liberator Kalina (EMBETH DAVITZ), Arthur and others set out to find the kids, all while attempting to avoid the various ghastly ghouls who are let loose one by one and are now after them.