Homer sends Marge and the kids to Santa's Village (in July) so that he can secretly make a porno movie with Fat Eddie as a way to pay off gambling debts. When the family unexpectedly returns home early, Marge walks in on Homer and Fat Eddie shooting the movie. Marge is outraged and leaves the house by herself. She meets a marine biologist, and she joins him in his effort to save the manatees. She tells him her story, and he tries to convince her that if she returns to Homer, he will not appreciate her, because he only cares about himself. Homer takes the kids to look for Marge. When he finds her, Marge refuses to return. Homer tries to prove his love to her by going on his own to save the manatees. While doing so, he is almost killed by jet skiers and the mob, because of the gambling debt he still owes, since the porno failed due to Homer's growling stomach ruining the audio. By attempting to save the manatees, Homer shows Marge that he does care about her, and they eventually reconcile.
"The Girl Who Knew Too Little"
The Simpsons object to a stamp museum being built in the lot next store to them. After winning the fight, the plans are changed to build the museum where a cemetery lot is located. The cemetery is then relocated to the same lot next door to the Simpsons. Lisa quickly develops great fears of the cemetery, which can be seen from her room, and she is unable to sleep. She tries to sleep in her parents' bed. However, they try to show her that her fears are irrational by sleeping with her in her room. After one night, they also become fearful of the cemetery and attempt to seek help from a psychiatrist. Lisa decides to conquer her own fears by spending a night alone in the cemetery. She slips and is knocked out after hitting her head on a tombstone. While unconscious, she sees herself in a confrontation with monsters, and she does not back down. They eventually let her know that it is fine for her to be a kid.
"Milhouse of Sand and Fog"
After Maggie is diagnosed with chicken pox, Homer hosts a party and charges money for parents to bring their kids over in an attempt to be infected. At the party, Marge successfully tries to reunite Kirk and Luann. When Millhouse sees what is happening, he decides that he would rather have his parents separated, because he enjoyed having them compete for his love. He and Bart form "Operation Reverse Parent Trap," and try to re-break them apart by putting Marge's bra in Kirk‘s closet, an idea they got from an episode of The OC. After Luann discovers the bra, she shows Homer, which causes a conflict between Homer and Marge. Bart tries to reunite them by making a dummy of Bart fall off a cliff into a river with huge rapids. After the plan does not work, Bart is actually in danger. Marge and Homer then work together to save him and are reunited.
"Treehouse of Horror XVI"
The "Treehouse of Horror" episodes always tell three different short stories.
"Bartificial Intelligence"
After unsuccessfully jumping from a roof into a swimming pool, Bart is in a coma. The Simpsons invite a robotic boy in an attempt to deal with the absence of Bart. They quickly grow to love the boy, who they like more than Bart. When Bart comes out of the coma, the Simpsons want to keep both boys. Bart finds himself competing with the robotic boy, who does everything better. Homer decides to abandon Bart and leaves him on the side of a road. Bart befriends a group of broken robots and takes their parts to become a cyborg to get back at his family. He then accidentally cuts Homer in half, turning Homer into a cyborg.
"Survival of the Fattest"
Homer is invited to a hunting party at Mr. Burns' place. When Mr. Burns sees that Homer thinks that the grizzlies are doing the hunting, he likes the idea and orders them to do the chasing. The hunt is televised, and Marge sees that Homer's life is in danger. She goes to save him, and knocks out Mr. Burns and Smithers right before they are ready to kill Homer.
"I've Grown a Costume on Your Face"
A witch puts a spell on the Springfield residents after Dr. Hibbert wins a costume contest over her. Everyone takes the form of his/her costume. Since Maggie is dressed like a witch, Lisa realizes that she can reverse the spell. However, some people like their costumes and want to remain under the spell. Finally, Maggie turns everyone into giant pacifiers.
"Marge's Son Poisoning"
At a store clearance sale, Marge buys a tandem bike and Homer buys a dumbbell. After a failed attempt to get a family member to ride with her, Marge decides to give the bike away. Bart feels badly and offers to ride the bike with Marge. They have such a good time that Bart chooses to spend more time with Marge than with his friends. Homer then feels left out. Since he now has one muscular arm after only using the dumbbell on one arm, he enters an arm wrestling competition with the help of Moe. After being teased by his friends about spending all his time with his mother, Bart makes negative comments about his mother in front of her. Although Bart feels badly and returns to Marge, she sends him back to his friends and is thankful for the quality time they spent together. Homer then returns to spend more time with Marge after winning the tournament.
"See Homer Run"
Lisa feels rejected after Homer likes Bart's Father's Day Toolman present better than the book she made him. She develops DDD (Disappointed Daughter Disorder). After Bart steals the "Bart Boulevard" street sign, a huge car crash occurs in the area. Consequently, Mayor Quimby decides to conceive The Safety Salamander spokesperson. The residents of Springfield are still upset with the Mayor and decide to hold a recall election. Homer becomes the spokesperson in an attempt to make Lisa happy with him again. He does a good job, and Lisa encourages him to run against Mayor Quimby and the other candidates in the election. After Homer's Safety Salamander suit falls apart during the final debate, the Mayor is re-elected.
