Marin and Wakana have a successful first cosplay event. Because of something Wakana said, Marin's mental and emotional state starts to change a little. Even though she was just spending time at the Gojos' home with Wakana and Kaoru to wash her outfit, she can't seem to calm down. Meanwhile, a certain person comes to Gojo Dolls after seeing the photos Marin posted onto social media of her Shizuku cosplay.
She finds out that her beloved 
older sister Neon is the enemy...
...تكتشف بأنّ أختها الكبرى التي تحبّها نيون هي العدوّ
Sie erfuhr, dass ihre geliebte
Schwester Neon ihre Gegnerin war.
Quand elle a su que
sa sœur était son ennemie…
Scopre che la sua adorata 
sorella Neon è il nemico...
Ela descobre que Neon, sua amada
irmã mais velha, é sua inimiga...
Её старшая сестра Неон
оказалась злодейкой.