Tamao Tsukamu is recruited by the beautiful and popular Kiritani Konome to join the Yearbook Committee for a "special duty." He soon discovers that his role is to serve as the male partner for third-year girls to help them complete the school's legendary "Hamedori Album," a collection of explicit graduation photos. After his first encounter with a senior student, Tamao commits himself to the task under Konome's watchful eye.
Tasked with completing the school's erotic "Hamedori" graduation album, Tamao works alongside the admired Konome-senpai to collect photos from third-year female students. From a private session with Matsudo Iori to a wild encounter with the swimming club, Tamao indulges in various sexual escapades to fill the pages. However, despite his hard work, he discovers that he is still only halfway to meeting the Student Council's requirements.
Tamao enters the "Girl-Gamble Challenge" to convince Miyanagi Sena, a famous erotic pinup idol, to join the school's "hame-dori" album. By correctly guessing her favorite professional works through a deep understanding of her philosophy, Tamao wins the bet and discovers that the provocative star is actually a virgin. While Tamao celebrates his victory, the student council VP hints that the next challenge will put his very life on the line.
After winning a gamble battle against Kizaki Caldina, Tamao Tsukamu claims his prize by filming an erotic video with her, which quickly escalates into a group orgy with Caldina's circle of friends. While Tamao's sexual prowess catches the eye of the school's elite, who view him as a potential political asset, a darker scheme begins to brew regarding his fiancé, Konome, and the power dynamics of their arranged marriage.
After discovering that Student Council President Sasugaki is using the school's sex photo graduation albums as prostitution catalogs, Tamao challenges him to a brutal hardcore match to end the exploitation and free Kiritani Konome. Despite being physically overwhelmed and witnessing the cruel humiliation of his seniors, Tamao taps into his inner spirit to overcome the President's strength. Emerging victorious, Tamao secures the album and immediately challenges Konome to a gamble match of his own.
Tamao faces a high-stakes duel against Kiritani Konome, a disciplined kendo master who views her commitments as absolute. By overcoming her overwhelming killing intent and breaking her "shell" as a swordsman, Tamao wins her heart, leading to a passionate confession and a promise of marriage. Following their victory, Tamao discovers the school's secret tradition of creating a "Hamedori" graduation album and is encouraged by Konome to join the committee.