Monsters vs. Aliens follows the story of Susan Murphy (Reese Witherspoon) as she transforms into Ginormica after being hit by an asteroid during her wedding. She is taken into custody by a super-secret government agency where she meets the other captured "monsters": BOB (Seth Rogen), a blue gooey experiment-gone-wrong; Dr. Cockroach (Hugh Laurie), a "mad" scientist who accidentally turns himself into a bug; Missing Link (Will Arnett) is a lagoon creature who may be the link between fish and humans; and Insectosaurus, who is a gigantic bug. They are kept in their secret prison until Gallaxhar (Rainn Wilson), an alien warlord, sends his robot minions to Earth to steal the same space compounds that give Susan her special powers. Susan and her newfound friends must save the planet using their unique talents and in exchange, earn their freedom.