Hahari presents Rentarou and the girls with a set of baby onesies she made for everyone, explaining that she heard about Kusuri making a "become a baby drug". Kusuri affirms this, explaining that she has enough drugs and neutralizers for everyone, but taking the neutralizer less than an hour after taking the baby drug would kill them due to physical over-stress. Kurumi and Karane refuse to go along with this, prompting a meltdown from Hahari, in turn causing Hakari to lash out at her. Kusuri attempts to defuse the situation by playing fetch with a nearby cat using the baby drug vial, but this only causes the drug to envelop everyone on the roof except Rentarou and Hakari.
With everyone else having been turned into babies, Rentarou and Hakari dress the girls in the onesies Hahari made. They quickly finding themselves overwhelmed with the task of looking after them, from having to stop them from hurting themselves to having to mediate quarrels between them. Their initial efforts quickly cause the girls to start crying, but they eventually get a break when Rentarou throws himself across the roof over and over again, getting the girls to laugh until they fall asleep. During the recuperation, Rentarou tells Hakari about what her mother told him about her, and Hakari contemplates how much of her life Hahari dedicated to raising her.
After everyone is restored to normal, Hahari whines about having been turned into a baby with everyone else. Hakari, however, apologizes to her mother about lashing out at her earlier, explaining that she understands how much effort she put into raising her. As the two embrace, Kusuri discovers a surplus supply of baby drugs on her person, prompting Hahari to suggest a rerun of the experiment.
Tropes:
- All Animals Are Dogs: Kusuri tries to play fetch with a cat. As Shizuka points out, that's a game for dogs.
- Amusing Injuries: Rentarou entertains all the girls by throwing himself face-first across the roof.
- Baby Morph Episode: Kusuri has drugs that allow for this and the chapter opens with Hahari wanting everyone to use them so she can be mommy.
- Comically Missing the Point: Hahari thinks Hakari is upset at her because she's jealous of her trying to be everyone else's mommy and not just hers.
- Didn't Think This Through: Kusuri tried to play fetch with a nearby cat using the baby drug vial. The vial breaks and envelops everyone on the roof except Rentarou and Hakari.
- Terminal Transformation: Discussed. Kusuri explains that neutralizing the baby transformation drug less than an hour after it's administered would overstress the user's body and kill them.
