An elderly man named Irving Zisman undertakes a cross-country road trip to reunite his young grandson, Billy, with his estranged father. Along the way, they engage in a series of elaborate pranks on unsuspecting bystanders, capturing their genuine reactions to outrageous and often crude situations. Irving's crude behavior and outrageous antics cause continuous astonishment, bewilderment, and laughter among those they encounter. Whether it's disrupting a beauty pageant or a funeral, Irving's escapades emphasize his refusal to conform to societal norms and his willingness to push boundaries for comedic effect.

In addition to the pranks, the storyline also explores the development of the bond between Irving and Billy. As their journey progresses, moments of genuine connection and understanding emerge between the raunchy jokes and slapstick humor. Their interactions highlight themes of family, loyalty, and acceptance amidst chaos. Together, they navigate misunderstandings and societal expectations in a humorous yet heartfelt manner that juxtaposes the film's outrageous comedic scenarios.