“The Sweetest Apu” is the nineteenth episode of Season 13.
Apu's unbearable life of work and eight kids drives him to have an affair with another woman, and when Manjula finds out, Apu will have to do everything it takes to win her back.
Manjula brings the octupulets over to the Kwik-E-Mart to visit Apu, but unfortunately he becomes upset after the kids completely trash the store. Apu fusses at his wife and begs her to take their kids and leave, while Homer and Bart enter the store and buy beer keg for the American Civil War reenactment of the Battle of Springfield. After selling the keg, Apu confronts Homer and confesses that he is unable to handle his unloving wife and tiring kids. That moment, Annette, the Squishy lady, enters the store and begins to refill the Squishy machine. Homer watches Apu and Annette have a little conversation, then hints at Apu that she may like him. At the reenactment, Principal Skinner watches as Springfielders disobey him and hold a rather inaccurate battle, especially after the World War II veterans charge in with their tanks (Groundskeeper Willie pretends that they are Southern reinforcements). After the battle, Homer brings the empty, dented keg back to Apu in an attempt to get the deposit. There, he hears a giggle coming from a closet and finds Apu making love with Annette. He then walks backwards in shock all the way home to his bed (and promptly relives the experience in his brain).
Homer then proceeds to dream that Apu was at a harem, where Annette was one of the harem women. The dream ends where he tells Homer (who is a eunuch) to avert his eyes before he makes love with Annette. Homer wakes up in a shock (although he also consults the dictionary as to what a "eunuch" is, screaming in horror upon learning the definition). Marge then figures out what Homer saw judging from the rapid movements in one of his eyes. They both agree not to tell Manjula but while they are playing badminton, Homer and Marge act awkwardly around Manula and Apu, trying not to give out hints of Apu's adultery. Later, Homer and Marge confront Apu at Moe's and force him to try to break up with Annette. However, he cannot help it, as he is obsessed about her sexy behavior. That night, Manjula begins to suspect something when she notices Apu is not pressuring her for sex. She then watches the surveillance footage of the Kwik-E-Mart and finds out Apu's secret. Manjula then evicts her husband and he is forced to stay at the same apartment complex as Kirk Van Houten. To help get them back together, Homer and Marge invite Apu and Manjula to dinner, without telling either of them that the other one is coming. Their plan is unsuccessful, however, when Manjula demands a divorce.
While Manjula discusses her divorce with her lawyer, she realizes she still has feelings for Apu. She plans to cancel the divorce, when she comes home to see Marge teaching the octupulets their first words, which put together, say, “Mommy, will you let daddy come back...cookie!” Manjula is still having trouble forgiving him, when Marge suggests that she write down a list of things Apu can do to make it up to her and make him do them. Manjula agrees, so she and Marge go to Apu’s apartment and arrive in time to prevent him from committing suicide. Apu is then subjected to Manjula's list of tasks she provided in order to win her back. Apu is then forced to break up with Annette (Apu remarks that "that's a no-brainer"), lose weight, get a cartoon published in The New Yorker, change his name to Slime Q. Slimedog, wear a nametag that says said name, eat a lightbulb, and perform a Broadway show with all-octupulet cast. In bed, Manjula, finally satisfied after Apu completed all of the tasks, kisses him while Homer watches from the window on a ladder. The couple continues and Homer, traumatized, hops backwards on the ladder all the way home without falling, mimicking what he did earlier.