Dave Lizewski, a teenage comic book enthusiast, decides to become a superhero despite having no powers or training. Outmatched by New York's hardened criminals, Dave knows that what he's doing is dangerous, maybe even stupid, but with his superhero secret identity gaining fans, he has the itch, and it isn't going away.

The Ultimates, who are brought together by the United States government to battle superhuman threats, uncover a clandestine operation in which aliens are infiltrating the Earth.