LexCorp's CEO, Lex Luthor, has been elected President of United States during a severe nationwide economic depression. Under his leadership, the economy begins to thrive, and he assembles a force of government-employed superheroes consisting of Captain Atom, Katana, Black Lightning, Power Girl, Starfire, and Major Force. Meanwhile, Superman and Batman maintain their distrust toward Luthor.
Eight years after Harvey Dent's (Aaron Eckhart) death, the Dent Act grants the Gotham City Police Department powers which nearly eradicate organized crime. Feeling guilty for covering up Dent's crimes, Police Commissioner James Gordon (Gary Oldman) writes a resignation speech confessing the truth but decides not to use it. Batman has disappeared, and Bruce Wayne (Christian Bale) has become a recluse. Cat burglar Selina Kyle (Anne Hathaway) obtains Bruce's fingerprints from his home, kidnaps a congressman, then disappears. Selina hands Bruce's fingerprints to Phillip Stryver (Burn Gorman), an assistant to Bruce's business rival John Daggett (Ben Mendelsohn), in hope of having her criminal record erased. Stryver double-crosses Selina, but she uses the congressman's stolen phone to alert the police to their location. Gordon and the police arrive to find the congressman, and then pursue Stryver's men into the sewers while Selina flees. A masked militant named Bane (Tom Hardy) captures Gordon. Gordon escapes and is found by John Blake (Joseph Gordon-Levitt), a once-orphaned patrol officer who has deduced Batman's true identity from their similar backgrounds. Gordon promotes Blake to detective, with Blake reporting directly to him.
Batwoman employs the services of several young female agents known as "Batgirls", in her pursuit of justice. Her archenemy is a masked villain named "Rat Fink". Added to the mix is the President and Vice-President of the "Ayjax" Development Corporation. The company, using plutonium as its fuel source, has created a powerful listening device called "The Atomic Hearing Aid", which allows for limitless eavesdropping. The company has been ordered to destroy the hearing aid by the US Government when the government turned down the offer to buy the listening device (due to its unstable power supply) but the President of the company has refused to do so and now is being confronted by Rat Fink about selling him the device.
Une fausse bande annonce sur une équipe de super-héros tant attendue au cinéma : Superman et Batman se réunissent, malgré leurs différences, pour s'affronter Lex Luthor et Double-Face.