"K-ON! College" is a continuation of the "K-ON!" series, picking up after the events of "K-ON! High School." The manga focuses on the lives of the former members of the Light Music Club as they transition into college life. Yui Hirasawa, Ritsu Tainaka, Mio Akiyama, and Tsumugi Kotobuki enroll in the same university, while Azusa Nakano remains in high school, continuing her final year. The story explores the challenges and joys of adapting to a new environment while maintaining their passion for music and friendship.

At university, the group forms a new band, rekindling their musical activities. Yui, Ritsu, Mio, and Tsumugi navigate the complexities of college life, including academic pressures, part-time jobs, and new social dynamics. Despite the changes, their bond remains strong, and they continue to perform together, often reminiscing about their high school days. Azusa, though physically separated from the group, stays connected through visits and messages, providing a bridge between their past and present.

The narrative emphasizes the characters' growth as they balance their responsibilities with their love for music. Yui’s carefree nature contrasts with her efforts to adapt to a more demanding academic environment. Ritsu’s energetic leadership style evolves as she faces new challenges. Mio’s reserved personality is tested as she steps out of her comfort zone, and Tsumugi’s wealthy background adds a layer of humor and relatability as she adjusts to a more independent lifestyle. Azusa, now the senior member of the Light Music Club at Sakuragaoka High School, reflects on her time with the group while mentoring her juniors.

"K-ON! College" maintains the lighthearted and slice-of-life tone of its predecessor, focusing on the everyday experiences of the characters. The manga highlights themes of friendship, perseverance, and the passage of time, offering a nostalgic yet forward-looking perspective on the characters’ journeys. The story concludes with a sense of continuity, as the characters embrace their futures while cherishing the memories of their shared past.