On the day of his wedding to Helen (known as Elastigirl), superhero Bob Parr (better recognized as Mr. Incredible) unwittingly thwarts a suicide attempt by tackling a civilian through a skyscraper window. In the ensuing chaos, Bob encounters the supervillain Bomb Voyage, who is in the midst of robbing the building. However, his enthusiastic fanboy Buddy Pine, desperate to be a sidekick, interrupts the scene, but Bob turns him down. Unfortunately, Bomb Voyage manages to attach a bomb to Buddy's cape. Although Bob successfully removes the bomb, the explosion causes significant damage to an elevated train track, resulting in Bob having to halt an oncoming train unexpectedly. Following these incidents, Bob finds himself facing legal action from the suicidal civilian and injured train passengers. This, among other lawsuits, breeds a public disdain for superheroes, prompting the government to launch the Superhero Relocation Program, which forces all “supers” into hiding and prohibits them from using their powers in public.
Fast forward fifteen years, and Bob finds himself living a mundane life in Metroville with Helen and their children: Violet, Dash, and baby Jack-Jack. While he deeply loves his family, Bob longs for his past superhero exploits and is discontented with his current job as a claims adjuster, leading to a secretive vigilante life alongside his best friend, Lucius Best (alias Frozone). One fateful day, Bob's supervisor Gilbert Huph prevents him from stopping a mugging, leading to a heated confrontation where Bob injures Huph and is subsequently fired. In a twist of fate, a woman named Mirage presents Bob with a clandestine offer to tackle a giant robot called the “Omnidroid,” which has been wreaking havoc on Nomanisan Island. Bob accepts the challenge and cleverly tricks the robot into detaching its own power source. This thrilling experience revitalizes Bob, prompting him to strengthen his family bonds, get back in shape, and request superhero costume designer Edna Mode to repair his old suit after a mishap with the Omnidroid. Assuming that Helen is aware of Bob’s new work, Edna prepares new suits for the entire Parr family.
However, upon returning to Nomanisan, Bob uncovers a shocking truth: Mirage is working for Buddy, who has now adopted the name “Syndrome” and is bitter about Bob's earlier rejection. Syndrome has acquired wealth by creating weapons that emulate superpowers and is determined to train the Omnidroid to eliminate superheroes. His malevolent plan hinges on unleashing the Omnidroid in Metroville and then defeating it to cement his image as a hero. He aims to make the term "super" obsolete by selling his inventions worldwide.
Meanwhile, Helen visits Edna and learns of Bob's clandestine activities. In her attempt to locate him, she activates a tracker in their suits, inadvertently compromising Bob’s position while he’s on a stealth mission within Syndrome’s lair. Determined to rescue Bob, Helen commandeers a private plane, with Violet and Dash secretly aboard, leaving Jack-Jack in the care of a babysitter. Despite acknowledging the presence of children, Syndrome retaliates by shooting down the plane, yet Helen and her kids manage to survive and reach the island. Disheartened by Syndrome’s ruthlessness, Mirage liberates Bob who then reunites with his family. Together, Violet and Dash use their powers to fend off Syndrome’s guards and reach safety.
As the situation escalates, Syndrome pursues the family to Metroville. Using her abilities effectively, Violet frees her family, and with Mirage’s assistance, they confront the looming threat. During the fray, the Omnidroid turns on Syndrome, disarming him, and a fierce battle ensues between the Parrs, Lucius, and the robot. As the family retrieves the remote control, Bob seizes the opportunity to destroy the Omnidroid’s core, achieving a hard-won victory in the eyes of the public, just as Syndrome regains consciousness to witness the outcome.
Upon returning home, the family’s joyous moment is marred when Syndrome kidnaps Jack-Jack, intending to raise him as a sidekick. As he attempts to escape, Jack-Jack's latent superpowers abruptly manifest, allowing him to break free. Helen heroically saves her falling child, while Bob bravely hurls his car at Syndrome’s aircraft. In a dramatic turn of events, Syndrome is ultimately defeated when he gets caught in the plane's engine, leading to a catastrophic explosion.
Three months later, as the Parr family settles back into their lives, they find themselves confronted with the arrival of a new supervillain, the Underminer. Resolute and ready, they don their masks and suits, prepared to combat this new threat.
