Kippei is busy trying to become Kokoro's boyfriend and slips back into his irresponsible ways. He oversleeps and doesn't have time to make Yuzuyu's lunch. Even worse, he spends an afternoon with Kokoro, forgetting to pick up Yuzuyu at kindergarten. Yuzuyu feels like she has become a burden to Kippei, so she decides to walk home by herself ... and ends up disappearing!

Kippei has a lot to figure out, like what to make for Yuzuyu's lunch and how to drop her off at kindergarten while still getting to high school on time. Kippei is enjoying his time with Yuzuyu, but not everyone is happy about it. The girls at school miss their quality time with Kippei, and one decides to play dirty to get him back.

A stranger is seen lurking around the kindergarten, and Kippei is asked to investigate. When he finds the stranger, he recognizes his Aunt Miyako--Yuzuyu's mom! Kippei confronts Miyako and learns why she left Yuzuyu in the care of Kippei's family. Kippei wants to reunite Yuzuyu with her mother, but is Miyako ready for such a step?

Kippei can't understand why Kokoro is acting distant and refuses his touch. She hasn't told him about Itagaki, a boy who confessed his love and forcibly kissed her even though she refused him. Kokoro is too scared to talk about it, but if she doesn't open up soon the situation could get worse.