"BanG Dream! Girls Band Party!: 5th Anniversary Animation" is a special anime installment celebrating the fifth anniversary of the multimedia franchise "BanG Dream!" The story revolves around the interconnected lives of several all-girl bands, each with their unique musical styles and personalities, as they navigate the challenges and joys of performing together. The narrative primarily focuses on Poppin'Party, Roselia, Afterglow, Pastel＊Palettes, Hello, Happy World!, RAISE A SUILEN, and Morfonica, showcasing their individual journeys and collaborative efforts.

The plot centers on the bands preparing for a grand live concert event, which serves as a culmination of their hard work and dedication. Each band faces its own set of struggles, from overcoming creative differences to managing personal insecurities. Poppin'Party, led by Kasumi Toyama, strives to create a memorable performance that resonates with their audience. Roselia, known for their intense and polished sound, grapples with maintaining their high standards while fostering deeper bonds within the group. Afterglow, with their rock-centric style, focuses on balancing their passion for music with their friendships. Pastel＊Palettes, an idol band, works to refine their image and connect with fans on a more personal level. Hello, Happy World!, with their cheerful and eccentric approach, aims to spread joy through their music. RAISE A SUILEN, a newer and more experimental band, seeks to establish their identity in the competitive music scene. Morfonica, blending classical and rock elements, explores the emotional depth of their performances.

Throughout the story, the bands support one another, highlighting the themes of camaraderie and mutual growth. The narrative emphasizes the importance of perseverance, teamwork, and the transformative power of music. The concert event serves as a pivotal moment, bringing all the bands together in a celebration of their shared passion and achievements. The story concludes with a sense of fulfillment and anticipation for the future, leaving viewers with a heartfelt appreciation for the bonds formed through music.