CGI-animated sci-fi action film for kids. When a meteorite from outer space crashes into a young girl, Susan (voiced by Reese Witherspoon), and turns her into a 50-foot monster, she is taken to a secret government compound where she meets a ragtag group of monsters who have been similarly rounded up and hidden away. As a last resort on the part of the government, the motley crew of monsters are called into action to fight an army of invading aliens. Can Susan and her fellow monsters save the world from imminent destruction?