"Forgive and Regret" is the eighteenth episode of Season 29. As of this episode, the Simpsons have officially surpassed Gunsmoke to become the longest-running scripted prime-time US television series by a number of episodes.
Grampa Simpson admits to Homer about his correlation and comes to realize that the issue will not be easy to reconcile when he makes a recovery.
The episode begins with an opening parody of Gunsmoke, and then cuts to the episode. It shows Homer eating as many of Moe's hard-boiled eggs as possible for 50 dollars, but fails. While driving home, he accidentally knocks over a streetlight. A man appears, asking Homer to sell his car for $500, which he accepts because his car will be used in a demolition derby.
While at the derby, Grampa has a heart attack, and faced with the solution to either watch the rest of the derby and see his car win, or transport his father to the hospital, Homer agrees to help him. On his deathbed, Grampa makes a startling confession to Homer, whom he forgives.
However, Grampa survives, and Homer is still uncomfortable over Grampa's statement. The confession is eventually revealed to be that Grampa got rid of the pie recipes that Homer's mother, Mona, used to make when Homer was a boy. They were special to Homer because while Grampa was vicious and abusive to him, Mona helped Homer cope through baking. She also wrote quotes on the back of each recipe card. Grampa, who now feels guilty of what he did many years ago, goes to the place where the family lived in their day to locate them. Homer gets mad at Grampa for being mean and lying.
When the Simpsons go to find Grampa, Homer plans to thwart his scheme because the recipe box is still resting on a cliffside, and Grampa could risk certain doom getting them. Homer helps him to safety and to get the recipe box, and for a minute Grampa looks like he is sacrificing himself so that Homer can reach it, but when Homer gets to it, he lands on a bed that he got rid of years earlier. However, the box is empty.
While at a nearby restaurant, Homer recognizes the taste of the pie he is eating as the same one he and his mother used to bake. The waitress tells him that she found the recipes falling down the cliff when Grampa tossed them out and gives them to Homer, wrapped in a bow, and Homer and Grampa make up and reconcile once again.
"Forgive and Regret" scored a 1.0 rating with a four share and was watched by 2.47 million people, making it Fox's highest viewed show of the evening.
Dennis Perkins of The A.V Club gave this episode a B-, stating, "To the show’s credit, the episode itself makes only passing mention of the at least numerically impressive feat, with the cold open seeing a once-again pistol-packing Maggie gunning down Gunsmoke’s Marshall Matt Dillon. Credited to Simpsons writing stalwart Bill Odenkirk, ‘Forgive And Regret,’ instead, dedicates itself to telling a single story, once more revisiting the justifiably fraught (on both sides) father-son relationship between Abe and Homer Simpson.