Mayuri’s character arc explores the tragedy of a "life born to disappear." Her final confession—that she was born to love Shido rather than just serve a functional purpose—serves as the emotional core of the film.

As Shido successfully completes his dates, Mayuri's role ends, meaning she must disappear. However, she develops her own feelings for Shido, causing her Angel, Kerubiel , to react to her latent jealousy and go berserk.

The film is set following the events of the second season of the anime. Peace in Tengu City is disrupted by the appearance of a massive, invisible sphere emitting spiritual waves that only Shido Itsuka can perceive.

Throughout these dates, Shido is shadowed by Mayuri, a girl with long blond hair and pink eyes. She eventually reveals herself as an "overseer" created to judge the balance of power between Shido and the Spirits.