Plot: It's been one year since seventeen year old Kale Brecht's father, Daniel Brecht, died, and Kale isn't coping well since he largely blames himself for the death. An incident associated with that inability to cope leads to Kale being sentenced to three-months house arrest for assault, he adorned with an ankle monitoring bracelet to ensure he does not step off his mother, Julie Brecht's, property. Bored, especially as his mother cuts off many of his privileges, Kale largely spends his time spying on his neighbors, most specifically his new classmate, the pretty Ashley Carlson, whose family just moved in next door. Ashley, who ends up introducing herself to Kale in her own boredom in needing to get away from her parents, and Kale's best friend, Ronnie Chu, join Kale in watching the goings-on of their neighbors. At first, they somewhat jokingly muse that one of the neighbors, seemingly fastidious Robert Turner, may be the culprit responsible for the recent disappearance of a woman in Austin, Texas based on a circumstantial piece of evidence they see. But the more and more they watch, the more and more Mr. Turner's activities seem to be suspicious in actually being able to commit violent crimes against women. Just when Kale believes he has the first solid piece of evidence - enough at least to delve into it further - Mr. Turner enters their lives in a more personal manner. For Kale, this becomes a dangerous game of cat and mouse with Mr. Turner, he believing that Mr. Turner not only is killing women, but that he knows they have been spying on him. To some extent, Ashley and Ronnie are willing participants in the game, understanding the dangers, but Kale's mom also becomes unwittingly embroiled in the danger, that danger especially if Mr. Turner is indeed what Kale thinks he is. Through it all, Kale is placed in the disadvantage that it is his word against Mr. Turner's - he convicted of a violent offense - and that he is confined to his mom's property, more than ten seconds outside the perimeter which alerts the police.
Alternative Plot: Ever since his father died, young Kale (Shia LaBeouf) has become increasingly sullen and withdrawn, until he finds himself under house arrest. With cabin fever setting in, he turns his attention to spying on his neighbors, becoming increasingly suspicious that one of them is a serial killer. However, he wonders if he is right, or if his overactive imagination is getting the better of him.