Actor Rainier Wolfcastle holds a bankruptcy sale when his outer space restaurant franchise goes bust. The Simpsons purchase many interesting items, including a weight set, but when it comes time to load everything into the car, Homer is forced to use his Tetris skills to make everything fit. Eventually, Homer slides everything into place…but forgets to make room for himself. Marge drives the car back home, but along the way baby Maggie soils her diapers, forcing Marge to stop at the Kwik-E-Mart to use the bathroom. When Marge exits the bathroom, a scary-looking man points a gun at her and makes off with her necklace. Bart finds his mother staring ahead blankly, unable to move.

Marge and the kids returns home, where Wiggum and his men take her statement. But it quickly becomes obvious that an arrest isn’t likely. Homer gives Marge a whistle, pepper spray and a map of the most vulnerable parts of a man’s body to make her feel safer. Marge drives back to the Kwik-E-Mart but experiences a panic attack and makes her way home. In the process, she accidentally parks her car on top of the mailman. She attempts to go back outside to move the car, only to find that she’s paralyzed with fear. Dr. Hibbert diagnoses Marge with agoraphobia. He recommends she create controlled situations so she can leave the house without going into a panic. Despite her family’s kindness and help, Marge’s condition only grows worse, and she soon finds herself confined to the basement. With little else to do, Marge turns her attention to the weight set that Homer purchased at the Wolfcastle bankruptcy sale. She begins working out, and soon develops ab muscles. Feeling more confident, Marge makes her way into the backyard to pick a lemon from the lemon tree. She experiences another panic attack…and bursts a lemon in her hand. Realizing she’s now much stronger, she develops the confidence she needs to leave the house. She goes out for a run, and along the way bumps into the man who mugged her. She promptly beats him up. Later, Wiggum places him under arrest.

Marge makes her way to muscle beach, where she bumps into her old neighbor, Ruth Powers, who now sports an extremely buff body thanks to the years she spent in prison. Powers encourages Marge to consider going into competition…and turns her on to steroids. With the aid of additional workouts and the steroids, Marge grows even more manly and aggressive…so much so that Homer stops finding her attractive. The Women’s Bodybuilding Finals get underway and Marge wins the first runner-up prize. Her family reacts uncomfortably, as it only means Marge will work out harder to win first place. Home and Marge make their way to Moe’s bar. Through the open door, Marge spots the man who mugged her working on a chain gang. Marge storms up to the man and sends him hurling through a window into Moe’s bar (the three convicts shackled to him are hurled though the window as well). Marge’s rage continues unchecked, and she begins fighting with the other barflies, besting everyone in her path. Moe and Homer take refuge behind the bar, where Moe encourages Homer to do something. Homer stands up and reminds Marge that somewhere within her is the kind woman he married all those years earlier. Marge softens…and walks away with her husband. Later, Marge heaves the weight set into the furnace, along with pills, powders and needles. She then kisses Homer, scoops him up in her arms and runs upstairs.