Hirosuke Nakaido is a seventeen-year-old high school student defined by his average, normal demeanor and introverted nature. An immediate infatuation strikes him upon seeing Yasuna Ajimu at a train station. Their first encounter spirals into significant misunderstandings: a public molestation accusation and an accidental kiss when he falls onto her, cementing a negative initial impression. This clumsy introduction highlights his social inexperience and tendency toward awkwardness in emotionally charged moments.

Driven to resolve the misunderstanding, he actively pursues chances to apologize. Discovering Ajimu performs music at a local club and beach venue, he attends these events to approach her. Persistent efforts eventually succeed in clarifying the accidental nature of the train incident, paving the way for a developing friendship. Confessing his romantic feelings proves difficult, hindered by timidity and uncertainty about her emotions, especially after learning she harbors unresolved feelings for an ex-boyfriend.

His bond with Ajimu deepens amidst new romantic complications. Suzue Takemoto, a girl met through a friend, develops unreciprocated feelings for him, creating tension. A more significant obstacle emerges with the unexpected return of Ajimu's former boyfriend, Yuuma Otomine, seeking reconciliation. This love triangle intensifies his emotional conflict as Ajimu wrestles between her past attachment and her growing connection to him.

A critical turning point occurs when a truck strikes him, leaving him hospitalized and unconscious. This traumatic event forces Ajimu to confront her feelings, leading her to realize she loves him. His accident serves as the catalyst resolving their romantic uncertainty, solidifying their relationship by the series' conclusion. Throughout these challenges, he evolves from an initially awkward and hesitant teenager into someone capable of inspiring deep emotional commitment.