The students in Bart’s class receive their own video cameras as part of a creativity project. As thechildren ride home from school on the bus, Bart points his camera at Otto and begins an interview. But Ottohas something else on his mind: proposing to his girlfriend. The bus turns into a drive-thru restaurant and Otto pulls up to the take-out window. There, he proposes to his beloved Becky as heavy metal music blastsout of a boombox. Becky tells Otto to turn down the volume, then accepts his proposal.

Later, Marge receives a wedding invitation, only to realize that Bart told Otto he could have the wedding at their house. On the day of the ceremony, Marge approaches Becky as she adjusts her dress. Becky tells Marge that she and Otto have many mutual interests…with the exception of heavy metal music.

Later, as Otto and Becky walk down the aisle, heavy metal music fills the air. When Becky grows angered, Marge tells her that Otto must choose which is more important: his music or her. Moments later, Otto peels out in the school bus. With the wedding off, Bart tells Becky she can stay with his family until she straightens out her life.

Soon after, Becky is giving Marge little tips in the kitchen. When the family sits down for dinner, Homer and the children react favorably to the taste of the meal. Marge begins to feel as if Becky is upstaging her. But Becky s positive influence doesn’t end in the kitchen. She s soon performing Tae-Bo moves for Bart’s video project and helping Lisa with her saxophone. Patty and Selma tell Marge it won t be long before the attractive Becky usurps the family, seduces Homer and then kills her off.

While driving her car down a hill, Marge s brakes give out. Luckily, she encounters the world s largest speed bump and the car rolls to a gentle stop. Marge tells Chief Wiggum that Becky is trying to kill her. But Wiggum informs her that he is powerless to help.

Later, Becky treats the family to dessert at an ice cream parlor. When Homer is served a gigantic ice cream dish, he hyperventilates and loses consciousness, falling face-first into the ice cream. Thinking quickly, Becky yanks Homer out of the frozen dish and gives him mouth-to-mouth resuscitation. Homer revives, but Marge is so furious at what she perceives as a play for Homer, she begins hurling jimmies and brandishes a broken ice cream cone as if it were a weapon. Upon seeing this, Wiggum has her dragged off to a psychiatric hospital.

During a hearing, several psychiatrists declare Marge insane. Marge escapes and runs off into the streets of Springfield. Meanwhile, word of Marge s breakdown spreads throughout town, and she becomes the brunt of jokes on Krusty the Clown s television show. Marge disguises herself using the Comic Book Guy’s clothing and makes her way to the public library, where she researches Becky’s past.

When she comes up empty handed, she returns home and begins apologizing for her behavior. But upon seeing that the house has been transformed into a medieval torture chamber, she takes action. She kicks a knife out of Becky s hand, believing she was about to sacrifice Homer at an altar. But Marge realizes the elaborate costumes and set are all part of Bart’s music video project for school.

She also realizes that her car went out of control because Homer accidentally drained her brake fluid while he was changing her oil. Marge apologizes for the way she has been behaving, but shortly thereafter, Homer helps psychiatrists tranquilize Marge when she instructs him to "clean the house."