Puffless

"Puffless" is the third episode of the twenty-seventh season of the animated television series "The Simpsons", and the 577th episode of the series overall. It aired in the United States on Fox on October 11, 2015.
Plot.
Homer, Bart, Lisa, Maggie and Grampa are watching a Dr. Nick program (who did not realize his patient was pregnant and even mistook the umbilical cord for an astronaut tether) when Marge turns off the TV and tells them that it is her mother Jacqueline's 80th birthday and the family should visit her. Homer is reluctant to go, claiming that the Bouviers hate him, but does so for Marge's sake. At Jacqueline's house, while watching slides which include Marge's father, Clancy, the question about how he died is brought up, something that Marge, Patty and Selma never knew about. Jacqueline reveals the truth: her husband died of lung cancer but she did not say so before because back then, people were reluctant to admit it and she thought smoking made Patty and Selma look cool. This revelation shocks Patty and Selma, who decide to quit smoking once and for all and burn all their cigarettes, which causes Jacqueline's house to burn down.
At the DMV, Patty realizes how hard it is to quit smoking after years of addiction after thinking she was having a stroke. She also realizes that Selma is not affected by the sudden change of habits, and decides to consult Dr. Hibbert. At the hospital, Patty discovers that Selma relapsed ten minutes after quitting smoking. An angry Patty leaves Selma and stays at The Simpsons house for a while. Homer quickly gets annoyed by aspects of Patty's presence in his house such as her snoring while he and Marge are trying to have sex and accidentally seeing Patty in the shower. Meanwhile, at the apartment, Selma has a hard choice: quit smoking and reconcile with Patty or carry on smoking and lose her sister's respect. She decides to quit smoking and they reconcile.
At the end of the episode, Patty and Selma return to their apartment and quickly notice in the absence of cigarette smoke the noxious odors in a small apartment that include two aging women, a baby and an iguana. They quickly take up smoking again to cover up the odors, though are unsure if it will be a happy ending. A montage of their life and death through smoking is shown as Rick Astley's "Together Forever" is heard in the background. Even after their death, cigarette smoke is seen rising from their graves.
In a secondary plot known as "Maggie's Extraordinary Animal Adventure", Maggie befriends a squirrel who introduces her to other animals such as an owl, an opossum, and a parrot (which is revealed to belong to Duffman). However, Cletus captures the opossum for dinner and puts the captive animal under his dog's surveillance. Maggie makes a plan to fight against the Spucklers and free the opossum by assembling an army of animals. With help from Plopper the Spider-Pig, Maggie and the animals are able to free the opossum and defeat Cletus and his dog before going their separate ways, with the parrot returning to Duffman, having picked up some of Cletus's phrases.
Reception.
The episode received a 1.5 rating and was watched by a total of 3.31 million people, making it the most watched show on Fox that night.
Dennis Perkins of "The A.V. Club" gave the episode a C, saying "It’s exactly half an episode that seeks to tell a character-based story. That’s a steep hill to climb under any circumstances, but especially when trying to make us care about two one-note characters like Patty and Selma. Not that there haven’t been interesting, affecting Patty and Selma episodes in the past—honestly, Selma’s rejection of her sham marriage to secret ichthyophile Troy McClure is one of the most improbably heartbreaking endings in Simpsons history."