The film begins sometime prior to 1957, but never exactly stated, during a Golden Age of superheroes, when freelance costumed adventurers assist a grateful public with everything from freeing cats stuck in trees to foiling bank robberies.
Mr. Incredible saves a man attempting a suicide. He then foils a robbery by the villain Bomb Voyage, while also contending with the attention of Buddy Pine, a young fan who wishes to be his sidekick. When Bomb Voyage plants a bomb on the young would-be superhero, Mr. Incredible manages to dislodge it, causing a train wreck that injures 100 people. He then races to his wedding, where he marries Helen.
However, lawsuits from both the suicidal man and the victims of the train wreck force superheroes into a government-sponsored protection program similar to witness protection, in order to be given immunity from lawsuits in exchange for ceasing all superheroics.
Fifteen years later, Bob and Helen Parr settled into relatively normal suburban lives raising three kids, Violet, Dashiell ("Dash") and baby Jack-Jack. The children have powers which reflect their personalities.
Bob is contacted by a woman named Mirage, who knows his secret identity, and offers to hire him to subdue a renegade robot, the Omnidroid 8000, on Nomanisan, an uncharted island. Mr. Incredible completes the task, telling Helen and his family that he is going on a business trip, though his old super suit is damaged in the battle.