Peter Griffin's religiously devout father Francis is forced to retire from his job at the mill. Peter brings his dad to live with his family, though this brings trouble since Peter's wife Lois argues with Francis because she is Protestant and Peter is Catholic. Francis yells at his oldest grandson, Chris for masturbating in the bathroom when he is merely defecating, he makes his granddaughter, Meg, feel guilty for holding hands with Kevin Swanson, and tells his youngest grandson, Stewie, bedtime stories of the punishments that await sinners in hell. Francis and his teachings to his grandsons and granddaughter cause Chris to become convinced that defecation is a sin, while it makes Stewie become fascinated with God and his power to punish sinners.
Francis is soon hired at the Happy-Go-Lucky Toy Factory where Peter works; thanks to his excellent proficiency he is made foreman of the factory and fires Peter. Francis tells Peter he is a failure as a worker and a father, with this Peter gets tired of trying to please his father and at first does not know what to do, but then sees on the news that the Pope is visiting Boston. Peter decides to drive to Boston and "kidnap" the pope so that he could tell Francis what a good father and person he is. Peter takes the Pope to his house; when Lois sees him she is terrified that Peter kidnapped him. Although he kidnapped him, the Pope agrees to tell Francis what a good person Peter is. Before they go, Peter fixes the problems Francis had created for his grandchildren; he tells Chris that what happens in the bathroom is between him and God, to Meg that it is okay at her age to go out with boys, and tells Stewie about how loving God is.
Peter takes the Pope to the toy factory, where the Pope tells Francis that Peter is a good man and father. After hearing this Francis accuses the Pope of being soft; the Pope takes great offense at Francis's claim and starts yelling at him, threatening to excommunicate him. Peter intervenes, and when he reveals he wanted his father's love, Francis says that albeit he doesn't like Peter's personality, he loves his son, and Peter reconciles with his father. Francis is forgiven by the Pope and is hired for a job as a security guard for the Pope's tour of the United States. At the end of the episode, Peter's mom shows up at the door and wishes to live with the family, prompting them to jump in an escape pod.