That Locked Window - S2.E11

Hanayo explains that even though she herself has fallen in love with Kazuki, she doesn't want to betray Yuzuki. Kazuki overhears this and learns the truth, leading Hanayo to try and run off, only to suddenly collapse in the process and become hospitalized. As Yuzuki worries that Hanayo will disappear if she can't fulfil her wish, Yuki believes she can and Ruko might be able to reach Tama during a battle against Hitoe and Yuzuki. Sure enough, Yuki manages to get in contact with Tama, encouraging her to grant Ruko's wish alongside her. Together, they make Ruko an Eternal Girl, showing Hitoe and Yuzuki a glimpse of the white windowed room, where Kazuki theorises they may find the real-life Mayu. Ruko and Yuki arrive at the white windowed room to try and talk things out with Mayu, but Ulith also appears, declaring Mayu as her Selector and challenging them to a battle. As the two pairs battle, Yuki starts disappearing as a result of Iona returning to her original body, so Ruko takes her and goes off in search for Tama. Both Ruko and Hitoe's group then learn that the real Mayu is already dead, before Mayu attacks Yuki with a Level 5 attack.