The movie begins with Irving Zisman, who is an 86 year old man. But the way he behaves is just like the young people. This man’s relationship with his grandson Billy is shown in this movie. Irving is notorious and crazy, and he is a dirty grandpa. When Irving hears the news that his wife, Mrs. Zisman has passed away, he starts laughing out of joy.
When Billy, his grandson meets his grandpa, the duo forms an eternal bond. Irving goes out on the crazy road trip across America with Billy. The two unlikely companions enjoy their time and does the craziest things they can. This is the most insane and the craziest trip that has ever been captured on hidden cameras. The crazy Grandpa, along the way introduces his grandson to people, places and different kinds of situations. They will meet male strippers, mourning people at funerals and many of the unexpected citizens of America.