Hikaru Kusakabe is an ordinary teenager; he has a band, smokes, goes to parties, and enjoys his youth to the fullest. His classmate Rihito Sajou, on the other hand, is his complete antithesis; Rihito is an honor student who is always at the top of the class, and he received a perfect score in his high school entrance exam.

During rehearsal for a chorus festival, Kusakabe notices that Sajou is not singing and offers to help him practice. They start meeting every day after class to train. Because of this, even with completely different personalities, the two boys begin growing closer and developing feelings for each other.

With the pressure of the last year of high school, students are faced with the looming decision of their future. Along the way, these two boys will need to learn about their own feelings, all while supporting each other and growing together.

Doukyuusei was published digitally in English as Classmates by Digital Manga Publishing on April 29, 2014, and in print as Classmates: Dou kyu sei by Seven Seas Entertainment on June 4, 2019. It was also released in Spanish by Tomodomo Ediciones on November 14, 2014; in Polish by Waneko on February 25, 2016; and in German by Manga Cult on September 5, 2019.