Since her college days, 23-year-old Meiko Inoue has felt a demonic presence in Tokyo draining her drive, leaving her restless and yearning for her younger years. She questions her life's purpose. One day, Meiko mentions quitting her job to her boyfriend, Naruo Taneda, who sleepily agrees.
Encouraged by his drowsy response, Meiko impulsively leaves her position, chasing a fresh start, and Taneda soon follows. Together, they decide to revive Rotti, Taneda's former band. As they reconnect with old friends and prepare to perform again, life delivers an unforeseen and devastating blow—forcing Meiko and her friends to reassemble what has been broken.
Solanin tells an intimate story of love, loss, and grief, centered on twentysomethings who often fall through society's cracks.