When he is sentenced to three months house arrest, teenager Kale Brecht starts spying on his neighbors and becomes convinced that a serial killer lives next door.
After his father's accidental death, Kale (LaBeouf) remains withdrawn and troubled. When he lashes out at a well-intentioned but insensitive teacher, he finds himself under a court-ordered house arrest. His mother continues to cope, working extra shifts to support herself and her son, as she tries in vain to understand the changes in his personality. The walls of his house begin to close in on Kale as he takes chances to extend the boundaries of his confinement, both physical and emotional. His interests turn outside the windows of his suburban home toward those of his neighbors, including a mutual attraction to the new girl next door (Roemer). Together, they begin to suspect that another neighbor is a serial killer. Are their suspicions the product of Kale's cabin fever and vivid imagination?