Sixteen-year-old Cassie Sullivan is trying to survive a world devastated by the waves of an alien invasion, while trying to save her five-year-old brother Sam from a training camp that was created by the Others (the aliens).

A young woman becomes worried about her boyfriend when he explores a dark subculture surrounding a mysterious videotape said to kill the watcher seven days after he has viewed it. She sacrifices herself to save her boyfriend and in doing so makes a horrifying discovery: there is a "movie within the movie" that no one has ever seen until now.