After butchering a speech in front of all of his friends at work, Homer turns to improv comedy to gain back his confidence in his public speaking skills. Meanwhile, Marge decides to rebuild Bart’s lackluster treehouse, but tensions rise when Bart questions her building skills. Also, in the episode’s last three minutes, Homer appears LIVE for the first time on television (both for East and West Coast broadcasts) to answer fan questions. 
Homer was going to make an anual speech at the Nuclear Power Plant. His original plan was to repeat the comedy speech he did every year, however, most of his punchlines were already used or they would be offensive as Lenny's grandmother was sick. This made him so nervous that he passed out on the stage, leading to a trauma of public speaking. Trying to cheer Homer up, Marge took him to a standup comedy show.
At the show, Homer was amazed by the actor's talent to improvise. He, Lenny and Carl then agreed to join an improvisation class, where Homer learned that he has a tallent for improvising scenes. They chose to make their own standup comedy club at Moe's Tavern, where Homer's act was acclaimed by the public and the critics.
With such a success, Homer was invited to perform at the Springfield Fringe Festival, but Homer was insecure about his act. Moe advised him that he should cheat on his improvisation act, letting Moe pick his scenarios. However, Lisa found out about their plans and convinced Homer to make his show the proper way.
On a secondary plot, Bart and Lisa go to Ralph's birthday party, where Bart realized that Ralph's new treehouse (built with money that Chief Wiggum took from the evidence locker) is much better than his old current treehouse. Feeling envious, he chose to destroy his treehouse. However, when he mentioned that mothers can't build a treehouse, Marge planned to work hard and build him the best treehouse she could.
Later, at the new treehouse, Marge overheard Bart saying to Milhouse that there wasn't any need to thank her, as she was only doing her job. Marge got ticked off at him, but the next morning, Bart took her breakfast into the master bedroom and apologized (with Homer's help), and they reconciled.
William: If Donald Trump becomes the president, are you going to move out of Springfield and possibly move to Canada?
Homer: Well, there are a lot of people who want me to move out of Springfield already, so... But I don't think Canada will want me to... Will welcome me. But you know what? That's why I'm for Bernie Sanders. I love his chicken, but out of respect, we should refer to him as the "Colonel".
Michelle: I was just wondering, after all these years, how would you finally get rid of Patty and Selma?
Homer: The best way is not to bathe, and I've been doing that for a month. But they smoke so much, it seems to cover up the odor. But I have to say, I'm getting a lot of time to myself!
Kathy: I drank too much this weekend, what is your best hangover cure?
Homer: Best hangover cure is to sleep on the lawn and stay there until Marge stops being angry.
Zachary: What's your favorite song?
Homer: What's my favorite thong? My favorite thong is that Brazilian one that... that doesn't pinch too tight around the waist.