"The Serfsons" is the twenty-ninth season season premiere of the American animated television series The Simpsons, and the 619th episode of the series overall. The episode was directed by Rob Oliver and written by Brian Kelley. It aired in the United States on Fox on October 1, 2017.

The episode places the citizens of Springfield in a medieval fantasy kingdom called Springfieldia, where the Simpson family are serfs known as the Serfsons.

This is the first Simpsons episode to be scored by composing team Bleeding Fingers Music since longtime composer Alf Clausen, who had scored the show since 1990, was dismissed from that position in August 2017. To date, this episode marks the final time that Apu is voiced by series cast member Hank Azaria and is the last dub of Homer's French-Canadian voice actor Hubert Gagnon following health issues, resulting in his death on June 7, 2020.^[1]

In the kingdom of Springfieldia, the Serfsons visit Jacqueline Bouvier at The Webs at Giant Spider Acres, a retirement forest, where Marge discovers, to her shock, that Jacqueline is freezing over.

At Barber Hibbert's Surgery, Jacqueline is found with progressive frozen mortification after having been bitten by an ice walker, which converts the victim's flesh to ice in the span of a week. To save her, he proposes a treatment, buying an Amulet of Warmfyre. However the cost for it is too high, and Marge sends Homer to grab the necessary money. Azzlan appears trying to get the Serfsons to convert to Christianity only to be driven away by Marge.

At the Springfieldia Human Power Plant, Homer attempts, unsuccessfully, to ask Lord Montgomery for the money. Seeing her father's plight, Lisa solves the problem by magically converting lead into gold. However, Lisa cannot perform magic in public as then she would be taken by King Quimby and be forced to become one of his evil wizards.

At home, Marge gives the amulet to Jacqueline, who refuses at first, recognizing the futility of life, though she decides to wear it. At that moment, King Quimby's wizards appear and take Lisa away, charging her with witchcraft. To rescue her, Homer rallies the town's peasants into revolt. Upon scaling the castle, the peasants defeat King Quimby's wizards only to face a dragon. Jacqueline decides to remove the amulet, turning her into a human composed of ice, and sacrifice herself to defeat the dragon in which she succeeds. However, it is revealed that the dragon was the source of all magic in the kingdom including all magical creatures. Lisa suggests that the kingdom can now base their lives on science, to everyone's dismay. Homer decides to light coals in an attempt to revive the dragon. This succeeds only for the dragon to burn the village down.

Executive producer Matt Selman described the episode as a love letter to the fantasy genre portrayed in different forms of media. In July 2017, Entertainment Weekly reported that Nikolaj Coster-Waldau would guest star in the episode as a character similar to Jaime Lannister, his character in the television series Game of Thrones.^[2] This episode marked that last time Hank Azaria voiced the character Apu following the controversy surrounding the character.^[3]

Dissatisfied with composer Alf Clausen's work, executive producer James L. Brooks attempted to hire composer Hans Zimmer, who worked on The Simpsons Movie, before hiring composer collective Bleeding Fingers Music, which was founded by Zimmer, and the producers fired Clausen. He is credited as composer emeritus starting with this episode.^[4]

In May 2019, several media outlets reported that this episode predicted the plot of the penultimate episode of Game of Thrones because this episode ends with the burning of the village, which is what happens in that episode.^[5][6]