The crew of Fraxinus sets about preparing for their battle against DEM with haste and high morale. The Spirits work hard to prepare snacks in order to encourage Shido and everyone else as the decisive battle draws closer by the hour...

A full-scale confrontation between Shido and his friends Ratatoskr and DEM has begun. Kurumi and her clone, AST led by Ryoko Kusabe, join them, and as the battle intensifies, Shido confronts a horde of pseudo-Spirits, Nibeelcole.

A certain time, a certain place. Shinji Takamiya encounters a spatial earthquake, but finds a girl at the scene. She remembers almost nothing about herself. Shinji gives her the name Mio and she goes to live with him and his younger sister, Mana.

Shido is flooded with memories as the girl named Mio Takamiya stands before him. She was the person with whom Shido once shared his feelings when he was Shinji Takamiya. Meanwhile, Kotori and the others learn of Reine's true identity.

As Shido rushes to the Spirits' side, Westcott blocks his path. Meanwhile, Tohka and the others find themselves overwhelmed and powerless before Mio's manifested Angel, Ein Sof Ohr.

Many spirits were exhausted by Mio's Ein Sof Ohr and collapsed. Kotori directs Fraxinus toward Mio and fires her spirit cannon, Gungnir, but...

Shido is shocked when Mio tells him that all the Spirits are dead. Stunned and unable to move, Mio nearly wipes his memories as Shido, but there is still one Spirit who's survived.

Shido returns to a time before the final battle with DEM began, when no one has died yet. In order to avoid repeating the same future, Shido asks Reine out on a date. After hearing the story from Shido, Kotori and the Spirits support their date.

As Shido's date with Reine is winding down, Reine comes to the realization that history has been rewritten. With DEM approaching, Kurumi arrives at their location to aid Shido.

Kurumi manages to survive Mio's assault and the other Spirits arrive to aid Shido. Realizing why he failed to seal Mio previously, Shido plans to kiss her again and this time make her choose him over Shinji.

While Shido and Mio face each other and convey their feelings, Westcott activates his terrifying ritual. Can Shido and the others stop his plot from achieving fruition?