Monsters vs Aliens combines B-movie nostalgia with futuristic technology to create an adventure for the whole family. When an alien attacks the Earth, the monsters must step up and become heroes to rescue humanity.
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?