Chiyo is disturbed to realize that junior high school students in love kiss one another in school. While she's confident that Rentarou is sincere and honest enough not to engage in such activities at his school, she soon finds all the girls kissing Rentarou on the roof. This prompts Chiyo to break them apart and forbid them from kissing on school grounds.
Some days later, the girls are struggling with not kissing at school. Hakari tries to pleasure herself, Shizuka kisses her book, and Meme disappears under Shizuka's dress. Nano can't focus on her studies or even rerail her thoughts, and Karane holds her pencil upside down. Mei accidentally pours water on Hahari's chest, and Hahari and Kurumi are drooling uncontrollably. Mimimi is unable to appreciate her own beauty, and Kusuri struggles with making a kiss simulation drug. The only one who remotely enjoys the kiss withdrawal is Iku, for obvious reasons.
Hakari rounds up all the girls to try and get Chiyo to kiss Rentarou. When he gets there, however, he says that he's willing to hold off if that's what Chiyo wants. Losing her remaining patience, Kusuri whips out her kissing zombie drug from Chapter 11, intending to use it on Rentarou, but she accidentally administers it to Chiyo. Before Rentarou can leave for the chemistry lab, Chiyo breaks off the doorknob. Chiyo tries to resist the drug's effects, but it's no use. All the other girls pin Chiyo down so Rentarou can escape, but their strength isn't enough to hold Chiyo. Hakari takes another dose of the kissing zombie drug and sandwiches Chiyo between herself and Karane, allowing Rentarou to break the door down.
After Chiyo is given the neutralizer, the other girls explain that they didn't want Chiyo to be forced into kissing Rentarou but wanted her to be happy about kissing Rentarou. Realizing her error in trying to shoehorn her beliefs into Rentarou's Family, Chiyo apologizes and asks Rentarou for a kiss. With the kissing ban uplifted, all the girls go for a round of kisses with Rentarou.
Tropes:
- Call-Back: The kissing zombie drug from chapter 11 returns.
- Detachable Doorknob: Chiyo breaks off the doorknob on the door to the roof, preventing him from getting back inside the school.
- Pun: When Mei pours water on Hahari's chest, the latter comments "These are I-cups, not teacups".
