After college, Meiko Inoue becomes fixated on a lurking demon in Tokyo, feeling stagnant and yearning for a more fulfilling life. Upon suggesting a radical change to her boyfriend, Naruo Taneda, he agrees in a daze, sparking a journey to rediscover their youthful aspirations. Embracing their past dreams, they resurrect Taneda's old band with friends, only to face an unforeseen challenge that shatters their plans. Through 'Solanin,' delve into a heartfelt narrative of love, sorrow, and growth as Meiko and her peers navigate the complexities of young adulthood.