Susan Murphy's (voiced by Reese Witherspoon) wedding day is rudely interrupted when from out of nowhere, she's hit by a falling meteor! Amazingly, she survives the collision and proceeds to walk down the aisle looking every inch the glowing bride... glowing green, that is. Things only get stranger once inside the church, as Susan suddenly grows to a colossal 49 feet 11 inches tall. Because of her new stature, she's branded a 'monster' and carted off to a secret government facility for genetic anomalies. There, she meets fellow outcasts; a brilliant cockroach with a PhD, a bizarre ape-fish hybrid, a gelatinous and indestructible blob, and a 350 foot grub.

When an alien robot with an appetite for destruction lands on Earth, a desperate President calls for the monsters to be released in the hope that they will defend the very people who imprisoned them. Of course, the monsters oblige as they are basically good, despite their outward appearance. In their clumsy effort to save mankind from the alien threat, they prove that they each have something valuable to offer and that together they can really make a difference.

DreamWorks Animation and directors Conrad Vernon (Shrek 2) and Rob Letterman (Shark Tale) have created a fun adventure packed full of B-movie references, eye-popping 3D visuals, and quirky-looking monsters kicking alien butt."