"Kawagoe Boys Sing" is a 12-episode anime series that centers on a group of high school boys in Kawagoe City, Saitama Prefecture, who form a choir club to pursue their passion for singing. The story begins with Kōki Hattori, a reserved and introverted first-year student at Kawagoe High School, who harbors a deep love for music but struggles to express himself. After a chance encounter with the school's choir club, he is drawn to the idea of joining, despite his initial hesitation. The club, however, is on the verge of disbandment due to a lack of members and interest.

Hattori is joined by four other boys: Shūichi Tsugawa, a confident and charismatic upperclassman with a natural talent for singing; Yūta Todoroki, a cheerful and energetic classmate who brings humor and enthusiasm to the group; Ryōhei Kurosawa, a quiet and serious student with a hidden passion for music; and Haruto Sugimura, a former delinquent who joins the club as a way to turn over a new leaf. Together, they work to revive the choir club, facing challenges such as recruiting new members, preparing for competitions, and overcoming their personal insecurities.

The narrative explores the dynamics of the group as they navigate the pressures of high school life, interpersonal conflicts, and their individual struggles. Each character’s backstory is gradually revealed, shedding light on their motivations and the personal growth they experience through their involvement in the choir. The series emphasizes themes of friendship, perseverance, and the transformative power of music, as the boys learn to harmonize not only their voices but also their lives.

As the story progresses, the choir club participates in local and regional competitions, showcasing their growth as performers and as a cohesive unit. The series culminates in a climactic performance that serves as a testament to their hard work and dedication. Through its focus on character development and the challenges of pursuing a shared goal, "Kawagoe Boys Sing" offers a heartfelt portrayal of adolescence and the pursuit of artistic expression.