Phineas Flynn was a kick butt superhero known as Mr. Improbable, until his heroics caused legal issues and it was decided that superheroes were banned. After that time he married fellow superhero Isabella, AKA Flexi-Girl, and had three kids, Adrian, Julia, and Thomas, who also inherit superpowers (minus Thomas). Phineas is called back into action when his archenemy resurfaces, but he'll need the help of his family.