Yui Kawa has just transferred to Class 3-5 at Ichio Junior High. According to her seatmate, Chie Uru, this school is home to many oddballs-some of them, in particular, the "oddest among all oddballs": five individuals with extraordinary appearances and equally extraordinary personalities, known as Kimengumi. Chasing after these unruly characters, Yui's unpredictable school life begins!

In the blink of an eye, the cast blows up-well, graduates from- Ichio Junior High and moves on to the next stage: Ichio High School! As the usual crew and a colorful group of new classmates gather, Rei is the only one missing…? / Yui, Kimengumi, and their classmates head to a bowling alley on a day off. A sudden bowling match kicks off, and Yui herself somehow ends up as the prize…?

Chie is furious with Yui, and the cause seems to be one of Yui's meddlesome remarks. Rei, who bumps into the furious Chie, starts talking to her about how kindness can backfire… / Jako Amano, the leader of Omegumi, is a contrarian. Both students and teachers tend to avoid her, as she always finds fault in everything, and Jako herself is well aware of this too, but still…

The freewheeling-as-usual Class 1-5 welcomes a new vice homeroom teacher today! Dreaming of becoming a passionate teacher in the old-school, Showa-era way, Mr. Jidai is left stunned by Kimengumi's eccentricity. / Wakazo Temekono, the school gang leader at Ichio High School, is searching for a successor. Spotting Dai, he sets out to toughen Dai up, only to find himself completely toyed with instead…

Kimengumi, Yui, and Chie visit Rei's house to hang out. In Rei's childhood photo album, they notice a boy who appears beside Rei in every picture…? Rei's fated rival, Don Harumage, enters the fray! / Don struggles to fit in with his new class as a transfer student. One stormy day, Don and Rei come across a mysterious creature. Naming it Pochi, the two bring the creature to school, but…

Chie is taking time off from school after breaking her leg. As the girls discuss visiting the injured Chie, Go, who is watching from afar, seems to have something on his mind… / Ms. Ikari and Mr. Sessa are getting married!? While the teachers aren't exactly displeased by the excitement among the students, they can't help worrying about Kimengumi, who have been invited to the wedding after-party…

Kiri Ichido is a straight-A honor student, but her perfect image is now at risk because of a home visit! The Ichido family is full of people she can't bring herself to introduce to her homeroom teacher…/Sho Kireide, leader of Irootokogumi, is as popular as ever. Meanwhile, Kiyoshi has just had his heart broken by what felt like love at first sight.

Yui and the girls head to the beach. The members of Udegumi are also there, apparently working part-time. Suddenly, something rises from the calm sea…it's Ja●s and the Umibozu!? / Kimengumi is so thrilled about the summer fireworks festival that the teachers' warning-"Don't go overboard!"-falls on deaf ears. However, Go has to help out at home that day…

Today is just another ordinary day for the Daima family, as Jin's parents try every possible way to wake him up. They somehow manage to send him off, but Jin's laid-back attitude doesn't stop, even after he gets to school. / Yui comes to school acting strange. The reason is that Rei showed up in her dream that morning. Meanwhile, Rei also seems to have something he wants to tell Yui…?

The students at Ichio High School are off on a school trip! Rumor has it that an extremely fancy dinner awaits them in the evening. Unfortunately, the leaders of each group are left behind as the bus departs! By the time they finally make it to the hotel, the dinner has already been completely eaten.

Yui is with Rei on their usual way to school. When they arrive at school, everyone seems to act different from usual. As they grow confused at the unfamiliar Chie and the members of other groups, another Yui and Rei appear!? What's more, their alternate versions have entirely different personalities and do not seem to get along at all…

Seeing the small park nearby, Kimengumi and Chie get excited as they reminisce about their childhood, and Yui can't help but feel a little envious. The group then decides to watch one of Rei's videos titled "I Ran an Errand Today!".