Melissa McCarthy and Susan Sarandon star in this road trip comedy co-written by McCarthy and her husband Ben Falcone, who makes his directorial debut. Tammy (McCarthy) finds her life in a mess after she loses her job at fast-food chain Toppy Jacks and discovers her husband Greg (Nat Faxon) cheating on her with neighbour Missi (Toni Collette). Deciding to leave town and head to Niagara Falls, Tammy, who is in need of money and a vehicle for the trip, has no choice but to bring along her grandmother Pearl (Sarandon). As their journey progresses it becomes clear that Pearl is an alcoholic and while trying to look after her, Tammy gets involved in various misadventures including the robbery of a Toppy Jacks.