Sadie Hoffmiller is in Boston, Massachusetts, with her boyfriend, Pete Cunningham, babysitting his three young grandsons. The boys insist that Mrs. Wapple, the woman who lives across the street, is a witch, and Sadie and Pete are anxious to distract the boys from such Halloween-induced ideas. Then Mrs. Wapple is attacked in her home, and Sadie finds herself embroiled in a series of unexplained occurrences with life-or-death consequences.