A 12-year-old girl and boy share a diary and call themselves boyfriend and girlfriend, and the show treats it with complete sincerity. There's no winking at the camera, no joke about how innocent childhood romance is. It just lets them exist in that small, genuine feeling of being chosen by someone who matters. The entire series is built on the quiet magic of being liked for who you actually are, even when you hate your own nickname.
Azusa hates her nickname. When Yuunosuke transfers to her fifth-grade class and casually mentions he actually likes being called Azuki-chan, something shifts. She develops an instant crush on this guy who gets her in a way nobody else does, and before she knows it, they're officially dating. The two start keeping a shared diary, writing notes back and forth like it's their own private world. It becomes a sweet ritual between them: confessing feelings, documenting their days, working through the small dramas that come with being twelve and in a relationship for the first time. Every page feels significant when you're that age. What follows is a comedy grounded in genuine middle school experiences. Misunderstandings happen. Their friends react. Families get involved. The diary sometimes says things that need careful explaining. Through it all, Azuki and Yuunosuke navigate what it means to genuinely care about someone when you're still figuring out who you are yourself. The show captures that specific awkwardness and sweetness of early relationships with warmth and humor.