Peter's mom gets a divorce. Peter feels abandoned until he sees a father figure in his mom's new boyfriend, Tom Tucker. Meanwhile, Brian gets his own NPR style show on the radio.

After Peters dad, Francis, dies, Thelma tells him that his real father actually lives in Ireland. So Peter and Brian decide to head there in search of his father, who ends up being the town drunk. They decide to play a drinking game to prove his paternity. Meanwhile, Stewie acts out and Lois spanks him. Realizing that he likes being spanked, Stewie does whatever he can to get into trouble.

Peter starts an anti-immigration group after being caught up in the pro-American sentiment at a Veterans' Day parade, but his tune quickly changes when he finds out he was born in Mexico. Unable to prove his citizenship, pass the naturalization test or convince investigators that his marriage to Lois is for real, he ends up working as a groundskeeper on his father-in-law's estate and leading the fight for immigrant rights.