American Dad is the animated story centers around the domestic life of its nominal title character, Stan Smith, a staunchly conservative Republican CIA agent, and self-proclaimed patriot. He is married to Francine Smith, a fairly ditzy housewife who is trying to make up for a wild youth. Their two children are Hayley Smith, a passionately left-wing college-aged activist, and Steve, an awkward teenage nerd. The Smith family is also in possession of two bizarre nonhumans — Roger, an escaped alien from Area 51 who Stan is covertly housing in defiance of his employer, and Klaus, a goldfish whom the CIA implanted with the brain of an East German Olympic skier.
Stan joins Roger and Steve's fictional detective agency, but he ruins the fun by being extremely incompetent at his job. Roger demands that Steve fire Stan, but Steve cannot bring himself to do it and ends up lying to Roger. Things take a turn for the worse when Stan is kidnapped, and Steve must tell Roger the truth.
When Stan finally has enough money to afford a membership at the golf club he has worked at for the past thirty summers, his hard work and perseverance prove to be futile when the club gives membership to Steve first. However, things are not all what they seem when Stan realizes who the club owner really is.
When Steve tries to prove his himself as a macho man to Stan, he follows in Roger’s footsteps and tries to change himself from the outside in with a superhero persona. Meanwhile, Francine is going through an identity crisis of her own when she receives surprising news that could change the family forever.
Father Donovan holds a Christmas play at the mall and casts Stan as Santa Claus and Roger as Jesus. But after the two get in a fight and cause a scene, Stan is kicked out of the church. Meanwhile, Hayley and Jeff adopt a child who turns out to be possessed.
When Stan runs into his former crush from CIA boot camp, his affection for her resurfaces, which drives Francine into a jealous frenzy. By including Roger in her plan for revenge, Francine accidentally leads him straight into the arms of a dangerous alien hunter.