Homer discovers that his mother is still alive, a former radical who is a fugitive from the law. When her old nemesis Burns spots her and tips off the FBI, she is forced to return to the underground.

Troy McClure hosts a behind-the-scenes look at the show, including clips of the series' beginnings as shorts on "The Tracy Ullman Show," Simpsons trivia questions, and unaired scenes from popular episodes.

Homer's mother returns, and after being cleared of all charges, is re-imprisoned on a technicality.

Homer's mother, Mona, returns, but Homer is reluctant to trust her because she abandoned him so many times as a child.

Karma gets the best of Homer after he gets his friends in trouble, and as a result, his bedwetting problem worsens. The family goes on a mission to infiltrate his dreams to search for clues in his subconscious to determine the source of his problem. But just as things take a dangerous turn in the dream, a figure from Homer's past appears, and he is finally reassured that the fond memories of his mother Mona (guest voice Glenn Close) remain alive, giving him just the right amount of reassurance to cure him of his problem.

Bart feels guilty after he wins the annual "last day of school" race around Springfield Elementary School, with help from Nelson, who beats up the frontrunner, Milhouse. Meanwhile, Homer tries to bring back 4th of July fireworks after they are canceled due to budget cuts.

The Simpsons learn about Grampa’s days in the Air Force, and Bart takes up smoking to impress Milhouse’s Dutch cousin, Annika.

Lonely Professor Frink uses science to turn himself into a man whom women find attractive. Then, overwhelmed by the attention, he invents an algorithm to perfectly pair the lonely men and women of Springfield, realizing that scientific exploration is his true love. Meanwhile, Marge, Bart, and Lisa visit Grampa for Valentine's Day and try to rescue the old folks from a drug-induced hallucination that allows them to relive their happiest memories.

All of the fast food restaurants in Springfield go healthy, forcing Homer to turn to the last bastion of greasy food for comfort.

Grampa makes a confession to Homer while on his deathbed. After his recovery, he comes to realize that this issue will not be easy to reconcile.

Todd blames God for the death of his mother and rejects his faith, so Ned sends him to live with the Simpsons, hoping they can scare him into believing in God again.

In a flashback, Homer goes on a road trip with his father to find his mother.