The most haunted house in the world sits on an isolated stretch of land that's 50 miles outside of San Francisco. Built by Sarah Winchester, heiress to the Winchester fortune, it stands seven stories tall and contains hundreds of rooms. To an outsider, it looks like a monstrous monument to a disturbed woman's madness. But Sarah's actually building a prison, an asylum for hundreds of vengeful ghosts -- and the most terrifying among them have a score to settle with the Winchesters.