Alisa Ayase, younger sister of Eli Ayase, transitions from a third-year junior high student to Otonokizaka High School, navigating cultural shifts after moving from her grandmother’s care in Russia to Japan. Her unfamiliarity with local customs surfaces in moments like mistaking oden for a typical drink purchase, underscoring her journey of adaptation. Cheerful and earnest, she wears her heart on her sleeve, channeling her admiration for the school idol group μ's—and Eli’s role within it—into heartfelt actions. When Eli hesitates to support μ's, Alisa challenges her sister’s reservations, pushing Eli to confront her true feelings and rejoin the group. Her emotional investment peaks as she tearfully praises μ's’ performances, moved by their passion and unity.

Alisa’s bond with Yukiho Kosaka, Honoka’s younger sister, grows from mutual idol fandom into a partnership. Choosing not to join μ's, they instead establish a new idol unit to honor its legacy without overshadowing it, valuing its irreplaceable impact. By the film’s epilogue, both lead Otonokizaka’s Idol Research Club as third-years, addressing incoming students with speeches celebrating μ's’ enduring influence and their resolve to uphold its spirit.

Her development intertwines loyalty with self-assurance, evident when she opposes Eli’s rigid expectations and champions her own goals. From a supportive sibling inspired by idols to a proactive leader shaping their future, Alisa’s path mirrors her dedication to preserving what she cherishes while carving her identity within it.