Fred (James Marsden), an out-of-work slacker, accidentally hits a bunny (voiced by Russell Brand) with his car. The bunny, named E.B., has run away from Easter Island because he doesn't want to take over from his father as the Easter Bunny—he wants to be a professional drummer instead.

Fred, who is initially startled by a talking bunny, takes E.B. to stay with him at the mansion he's house sitting. As Fred struggles with the world's worst houseguest, both will learn what it takes to finally grow up.