When Marge gets arrested for letting Bart go to the park unsupervised, she serves time only to realize that prison is a welcome break from the demands of her life as a mom and wife. In her absence, Homer struggles to manage all of the parenting responsibilities that Marge usually handles.
Homer was leaving the Power Plant for the weekend, as he promised Marge to be home for dinner. However, when he was leaving, Mr. Burns asked Homer for his help to fix a gas leak with a "Safety first" poster and to measure its level with a plumb bob (a procedure that takes hours to make).
At home, Marge was having trouble taking care of the kids. She was trying to help Lisa with a school project (dressing her as a male seahorse) and feed Maggie. However, Maggie spilled her food all over the room. Bart offered to help clean the mess, but he ended up causing even more mess with the chemical products. Marge became frustrated and asked Bart to go play outside. Bart went to the Springfield Park, where Martha Prince realized that he was by himself and called the police. The cops took Bart back home and arrested Marge for neglecting her son.
Marge was sentenced to ninety days on the Springfield Women's Prison. However, she realized that she could use the time to take a break from the stress of being a homemaker. Meanwhile, Homer was having trouble taking care of the kids, but some Springfield residents (especially Ned Flanders) realized that he was going through a difficult phase and planned to help him.
Back at the prison, Marge managed to fit in well. She used her hair as a weapon against bullies and made some friends, but Homer hired the blue haired Lawyer, who found out that Marge couldn't be arrested because of a technicality and she was set free. However, she realized that if she leaves the prison, all the responsibilities of being a homemaker would come back, so she fired a guard's gun and earned two more months inside.
In Springfield, other parents took Marge's prison sentence as a warning and agreed to overprotect their children, to the point of taking them on walks with the use of leashes. But the kids have had too much of their parents' attitudes and chose to sneak into the park to have fun by themselves, but their fun was ruined by a tornado. Meanwhile, Marge accidentally caused a prison break. In the midst of the mayhem, she found Homer undercover as a prison guard to help her escape safely. They manage to get back home, where Bart and Lisa have become overly attached to her. The episode ends with the entire family hugging inside the closet.