The episode begins with Homer Simpson enjoying a day at the Springfield Nuclear Power Plant, where he is seen working alongside his co-workers. During a routine day, he is approached by a new employee, who is revealed to be a young man named "Coot," who claims to be a long-lost relative of Homer. Coot's arrival sparks curiosity and confusion among the staff, particularly for Homer, who is intrigued by the idea of having a long-lost family member.

As the story progresses, Homer learns that Coot is actually his illegitimate son, a revelation that shakes him to his core. The emotional weight of this discovery leads Homer to reflect on his own parenting and the choices he has made throughout his life. He grapples with feelings of guilt and responsibility, questioning how he can be a better father to both Bart, Lisa, and Maggie, as well as to Coot.

Homer decides to take Coot under his wing, inviting him to live with the family. This decision is met with mixed emotions from Marge and the kids. Marge is supportive but cautious, while Bart and Lisa express their skepticism about Coot's intentions. The family dynamics shift as they try to accommodate Coot, leading to humorous yet tense moments as they navigate their new living situation.

As Coot becomes more integrated into the Simpson household, he begins to exhibit some of Homer's more questionable traits, such as laziness and a penchant for mischief. This behavior causes friction within the family, particularly with Bart, who feels overshadowed by Coot's presence. The tension escalates when Coot and Bart get into a series of competitions, each trying to prove their worth to Homer.

In a pivotal moment, Homer takes Coot to a father-son event at the local bowling alley, hoping to bond with him. However, the event takes a turn when Coot's competitive nature leads to a confrontation with Bart. The situation escalates into a chaotic bowling match, where both boys try to outdo each other, resulting in a series of slapstick mishaps that leave Homer feeling overwhelmed.

As the episode progresses, Homer begins to realize that he cannot simply replace his role as a father with Coot. He reflects on the importance of his relationship with his biological children and the unique bond they share. This realization prompts him to have a heartfelt conversation with Bart, Lisa, and Maggie, reaffirming his love for them and his commitment to being a better father.

In the climax of the episode, Homer confronts Coot about his behavior and the impact it has had on the family. Coot, feeling rejected and confused, reveals his own insecurities and desire for acceptance. This emotional exchange leads to a moment of understanding between Homer and Coot, where they both acknowledge their flaws and the complexities of their relationship.

The episode concludes with Coot deciding to leave the Simpson household, feeling that he needs to find his own path. Homer supports his decision, recognizing that while they may not be traditional family, they have shared meaningful experiences. The final scenes show Homer returning to his family, who embrace him, solidifying the idea that despite the chaos, their bond remains strong. The episode ends on a humorous note, with Homer accidentally causing a mishap at the bowling alley, leaving the audience with a sense of warmth and laughter.

Homer begins to question his paternity after a chance encounter with a man named 'Moe' who claims to have known his mother, Mona Simpson. This encounter triggers a series of flashbacks and memories that make Homer doubt whether Abe Simpson is truly his biological father.

Homer experiences a mix of anxiety and disbelief upon learning about the possibility of not being Abe's biological son. He feels a deep sense of betrayal and confusion, leading him to seek out a paternity test to confirm his fears.

Marge serves as a supportive yet concerned partner throughout Homer's journey. She encourages him to confront his feelings and the implications of the paternity test, while also trying to reassure him of their family's bond regardless of the test's outcome.

The flashbacks to Homer's childhood serve to illustrate his relationship with his parents, particularly his mother, Mona. They reveal the emotional scars and insecurities that shape Homer's identity and his desperate need for familial connection, which intensifies his fear of not being Abe's son.

Abe Simpson's character is explored through his interactions with Homer and the revelations about his past. The episode delves into Abe's own struggles with fatherhood, showcasing his love for Homer despite the potential revelation that he may not be his biological father, ultimately emphasizing the emotional bonds that define their relationship.