Jason Kelly [Zac Efron] is one week away from marrying his boss's uber-controlling daughter, putting him on the fast track for a partnership at the law firm. However, when the straight-laced Jason is tricked into driving his foul-mouthed grandfather, Dick [Robert De Niro], to Daytona for spring break, his pending nuptials are suddenly in jeopardy. Between riotous frat parties, bar fights, and an epic night of karaoke, Dick is on a quest to live his life to the fullest and bring Jason along for the ride. Ultimately, on the wildest journey of their lives, "dirty" Grandpa and his uptight grandson discover they can learn from one another and form the bond they never had.