Mikan Natsu attends junior high school alongside Sunao Moriyama as his classmate. Secretly, she nurtures a deep romantic affection for Sunao, yet her soft-spoken and timid nature prevents her from voicing these feelings. Instead, her unexpressed emotions manifest in vivid daydreams filled with romantic encounters featuring Sunao, complete with floating love bubbles and sparkling bishie auras. These fantasies often cause her to drift into a daze during class or daily life.

Whenever Mikan tries to get close to Sunao, Potemayo intervenes with aggressive hostility, physically attacking her. Undeterred by these assaults, Mikan continues her pursuit. Her emotional responses to romance reach extreme levels, sometimes triggering severe nosebleeds that necessitate hospital visits.

Complicating matters, Mikan's younger brother Yasumi Natsu regularly sabotages her attempts to interact with Sunao, irritated by her behavior. Amid her typically passive demeanor, Mikan once displayed unexpected courage by challenging Sunao about his dismissive treatment of his father.