"Love Live! The School Idol Movie" serves as a sequel to the "Love Live! School Idol Project" anime series, continuing the story of μ's, a group of high school girls who form an idol unit to save their school from closure. The film picks up after the events of the second season, where μ's has won the Love Live! competition, bringing attention and success to Otonokizaka Academy. With their goal achieved, the group faces the challenge of deciding their future as they approach graduation.

The narrative begins with μ's traveling to New York City for a special performance, marking their first international appearance. The trip serves as both a celebration of their achievements and a moment of reflection on their journey. However, the group begins to grapple with the uncertainty of what lies ahead. As third-year students Honoka Kosaka, Umi Sonoda, and Kotori Minami prepare to graduate, the remaining members must confront the possibility of disbanding. The emotional weight of their impending separation becomes a central theme, as each member reflects on their shared experiences and the bonds they have formed.

Throughout the film, the characters navigate their individual struggles and aspirations. Honoka, the group's energetic leader, feels the pressure of making decisions about μ's future while balancing her own dreams. Umi and Kotori, her closest friends, support her but also face their own uncertainties. The younger members, including Rin Hoshizora, Hanayo Koizumi, Maki Nishikino, Nico Yazawa, Eli Ayase, and Nozomi Tojo, each contribute their perspectives, highlighting the group's unity and diversity.

The film's climax centers on a final performance by μ's, symbolizing their growth and the enduring impact of their time together. The performance is both a celebration of their achievements and a heartfelt farewell, as the members express their gratitude to their fans and to each other. The story concludes with a sense of closure, as the characters embrace the future while cherishing the memories they have created.

"Love Live! The School Idol Movie" emphasizes themes of friendship, perseverance, and the bittersweet nature of change. It provides a fitting conclusion to the journey of μ's, offering fans a poignant and celebratory send-off for the beloved idol group.