For his entire life, Rod Kimble (Andy Samberg) believes his father, now deceased, was a successful and respectable stuntman working for Evel Knievel. He aspires to follow his father's footsteps and become a famous stuntman himself. Meanwhile, his stepfather Frank (Ian McShane) fails to respect Rod as a man, often going out of his way to beat him in sparring sessions and mocking his stuntman dream. While he makes many attempts at landing jumps with his moped, most of them end unsuccessfully. After an ill-fated jump attempt at the public pool, he returns home to find out that Frank is in urgent need of a heart transplant. Angry at the thought of his stepfather dying without gaining his respect, Rod goes to a forest to contemplate but ends up rolling down an enormous hill. At the bottom, he sees a sign that gives him an idea to save Frank. He tells his friends Rico (Danny R. McBride), Dave (Bill Hader) and his half brother Kevin (Jorma Taccone) about his plan to do a jump over fifteen school buses, and give the proceeds to his stepfather's surgery. He also adds Denise (Isla Fisher), his neighbor whom he has a crush on, to his crew.

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