Resolved to become a more independent person, Yukino Yukinoshita decides to smoothen things out with her parents, and the first step toward achieving that goal is to prove herself.

As graduation draws closer for the third-year students, Iroha Isshiki—the president of the student council—requests a graduation prom in collaboration with the Volunteer Service Club. Yukino accepts this request of her own volition, hoping to use it as a chance to demonstrate her self-reliance, but what lies ahead of her may prove to be a hard hurdle to cross.

Yahari Ore no Seishun Love Comedy wa Machigatteiru. Kan revolves around the graduation prom as emotions are poured into the preparations for the event. At the same time, a chance for the Volunteer Service Club members to better understand each other presents itself. And thus, Hachiman Hikigaya's hectic and bittersweet high school life begins to draw to a close.