Erza and Mirajane are abducted by the traitorous ex-Chairman Crawford Seam after unknowingly drinking a tea imbued with sleeping drug. Shortly afterwards, they are unconsciously taken to Cube, where Tartaros' headquarters is located. Howbeit, the two Fairy Tail Mages are separated, with Mirajane situated within a machine specialized in turning humans into Demons, and Erza brought and chained to a chamber; stripped naked by Kyôka.
Kyôka welcomes Erza to Tartaros, whose sole concern is Mirajane's current whereabouts and Crawford's condition. The former promptly informs her that the Chairman is fine, revealing that he is associated with Tartaros. Erza dismisses the news and questions Mirajane's condition once again, with Kyôka assuring her safety, but claiming that she shall soon be one of them. Erza struggles to break free, proving futile and leading Kyôka to begin her questioner regarding Jellal's location, which shocks Erza. Erza refuses to talk as she claims that she does not know, motivating Kyôka to utilize her Enhancement in order to attain the information she seeks. However, Erza assures her that she is clueless of Jellal's current location, only to be informed that Jellal is the third and final key to awakening Face, and that information contributing to his location would guarantee Mirajane's freedom; Kyôka continues to torture her while asking her questions about Jellal. Moments later, Erza lowers her head as blood drips from her body, with a distracted Kyôka gazing towards the apparent sound of Intruders. She orders Yakdoriga to stay with Erza whilst she goes investigate, warning the Demon not to touch her.
Shortly afterwards, Kyôka returns to the chamber where she is keeping Erza, telling Yakdoriga to use its electric-like ability to inflict damage upon her. Kyôka leaves the chamber once again, heading to Tartaros' control room and stabbing Crawford from behind after the latter announces that he was able to transfer the final key to his body. Meanwhile, Erza and the others on Cube feel a hefty vibration. She soon returns to where Erza is, only to find the shackles that were once surrounding Erza's wrist empty. Before she is able to react, Natsu and Lisanna grab her from behind, with an enraged Erza appearing along with a defeated Yakdoriga around her shoulders. With Kyôka now in Erza's prior position, the latter tells Natsu and Lisanna to search for Mirajane, as she will take care of Kyôka .
Erza begins her interrogation, asking Kyôka about the vibrations she felt earlier, only to be informed that it is the result of Face's awakening. Shocked, she believes that Jellal has been killed, but the Demon reassures her that Jellal is alive. Quickly, Erza proceeds to ask about Tartaros' goal; Kyôka explains that they intend to use Face to eradicate all Magic from Earth Land, for the sole purpose of reviving their master: E.N.D..
In the blink of an eye, Kyôka extends her claws and utilizes Erza's distraction to break free. With a smirk, she self-proclaims to of have fooled Erza, revealing that those who employ Curses are unaffected by restraints made to seal Magic. She dives in to ambush Erza, but the latter is rather quick to counterattack, successfully stopping the enemy's attack with her arm. In disbelief, Kyôka receives a kick to the face, which send she flying backwards. Erza, whilst staring at Kyôka , calls her a servant of Zeref. Kyôka , however, reveals that they are books written by the love of Zeref, naming herself a child of the Black Mage. She extends her claws further, but Erza is quick to dodge them and make use of her sword to match Kyôka's attacks. Moving in to attack Erza once again with her claws, she is caught off guard as Erza Requips her sword and armor, who uses the newly brought out spear to slam Kyôka onto the ground, and create a breach within Cube, where she finds her comrades fighting Tartaros.
Regrouping with the Fairy Tail Mages, Erza is informed that Mirajane is still within Cube. The Mages then throw themselves into Cube, using the breach Erza created. Erza sighs in relief, but is subsequently grabbed by Kyôka's extended claws and slammed onto the ground. As she lands, she tells Lucy to leave the fight to her, urging her to aid the others. With a smile across her face, Kyôka admits that she is starting to like Erza. Erza and Kyôka continue to clash, with Erza recognizing the enemy's strength. Albeit, Kyôka can only laugh silently. As the two continue their fight, Kyôka begins to realize that Erza's Magic Power has yet to vanish, questioning if the Face operation has failed.
Kyôka turns around and heads the opposite direction of Erza, leading the Mage to ponder if she is running away. Howbeit, as she continues to flee, she announces that she will leave the destruction of the fairies to "her". Now out of sight, Erza is shocked to see Minerva, who calls herself Neo Minerva, standing in her way and turned into a Demon. Meanwhile, Kyôka heads towards Master E.N.D. while asking herself if something happened to the Demon.