Susan Murphy is hit by a meteorite on the day of her wedding to weatherman Derek Dietl, absorbing a substance called quantonium and growing into a giantess. Alerted to the meteorite crash, the military arrive and capture Susan. She is labeled a monster, renamed “Ginormica” by the government, and sent to a top-secret prison facility headed by General W.R. Monger and containing other monsters: B.O.B. – a brainless, indestructible gelatinous blob; Dr. Cockroach, a mad scientist with the head and abilities of a cockroach; the Missing Link, an amphibious fish-ape hybrid; and Insectosaurus, a massive grub that is larger than Susan. The monsters are forbidden to have any contact with the outside world while the other monsters have been living contentedly with this lifestyle for the past 50 years…