- "When Bart discovers that a fifth grader has a scar identical to one Bart has, Marge tells him about a club of mothers she was in once where they set playdates for their kids; when she tries to reform the club, things turn out better for Marge than they do for Bart."
The 4th grade and the 5th grade classes of Springfield Elementary School are playing a dodgeball match. After other players are eliminated, there's only Bart and Erik left competing. Bart throws the ball to Erik but ends up hitting him, therefore winning the game. The 4th grade class congratulate Bart and praise him, but there's one slight hitch - the ball has hit off Erik and gone upwards. It falls back to Earth - ride into Erik's hands, therefore meaning that they win. This causes immediate and further tension amongst the students and teachers of both grades.
After the two grade classes fight in school, they decide to take it out of school, and when they do, Bart and Erik find something in common - they both have tiny sword-shaped scars on the backs of their hands. Neither of them have any clue what the marks are. In curiosity, Bart questions Marge and asks if she knows anything about the scars. Marge begins to tell Bart of when he was younger and how she used to take him to a "Mother and Me" group at a daycare centre called Toddlin' Town. Marge quickly became friends with the other women in the group there, and they formed "The Cool Moms". Bart proposes that the group get back together - and Marge does. However, when the group do get back together, only the moms enjoy the occasion. Bart finds himself constantly exhausted and bullied by the group, while the dads do not get along at all.
Bart is still imminent to discover how he got the scars, and ends up at Comic Book Guy's store, with Lisa along for the trip. Comic Book Guy releases, under pressure, the information Bart needs: Comic Book Guy had been hired to control the fireworks at Springfield High School's July 4th celebration seven years ago, where many of the town's citizens were picnicking and watching the show. The toddlers from the Toddlin' Town "Mother and Me" group snuck off and ended up at the fireworks control station. Comic Book Guy had his sandwich on the table, and was going to eat it quite soon. Bart and the toddlers each pressed a button, and the toddlers' actions ended up in the fireworks spiralling out of control and meaning that more fireworks were expelling than they should have been. One firework hit Comic Book Guy's sandwich, resulting in it burning and the 'sword forks' holding the sandwich together, to travel upwards into the air, and land on each of the toddlers' hands - the heat of the metal objects burning a tiny crater-like depression in the backs of their hands.
After getting the information needed, Bart and Milhouse plan to split the group up again by framing them for setting off a huge load of fireworks. They get hold of some, and tie them up in the garage, but Marge catches them red-handed. Milhouse is told to leave, which is when Bart reveals his true feelings towards the group. Before he and Marge leave, Bart ignites the firework lead. He leaves, and then Homer enters - to a firework explosion right in his face. At one of the Cool Moms' houses, Marge tells the group of Bart's plan. The others then reveal that Bart was always the bad apple of the group, causing Marge to flip out. She leaves before two of the moms engage in a make-out session, while the other looks on. Meanwhile, there is still friction between the dads of the group, who have yet to receive the news of the group's split. Homer's had enough and when Ned Flanders greets them all, he goes over to hug him!