Premise: "When California girl Susan Murphy is unexpectedly clobbered by a meteor full of outer space gunk, she mysteriously grows to 49-feet-11-inches tall and is instantly labeled a "monster" named Ginormica. The military jumps into action, and she is captured and held in a secret government compound. The world learns that the military has been quietly rounding up other monsters over the years, however their confinement time is cut short when a mysterious alien robot lands on Earth and begins storming the country.

As a last resort, under the guidance of General W.R. Monger (on a desperate order from the president), the motley crew of Monsters is called into action to combat the aliens and save the world from imminent destruction." -- based on the description from the official website