Posi and Nega scolding a frustrated Yuu for procrastinating on an art assignment she was charged sets the stage to have explained her a forest fabled to enable anybody to draw with a great deal of skill; desperate to avoid the turbulence for not doing her homework but also curious, Yuu decides to set course for the forest where Midori explains Miya Nakahara who prosecuted a prolific year-long art career a decade ago at only 13 years old before disappearing. Upon having it explained that Miya will catalyze sincere efforts to develop the artistic skills of those that draw in the forest, Yuu races off into the forest to try her fortunes only to find that success can have far more dire consequences than failure when she encounters the Unicorn Deshi who leads her into a face-to-face encounter with Miya in a pseudo-reality that she cannot easily leave on her own when the Unicorn Meijin takes her prisoner with the exhortation to reside in its world with Miya. Even though Miya yields to her conscience and decides to help Yuu return home, it ultimately does nothing to challenge the bitter reality that Miya is in a purgatory not unlike what Nega and Posi forewarn Mami of if anyone ever pays audience to her henshin.
Midori si offre di aiutare Yu a completare un disegno, portandola nella foresta incantata dove Mia, una giovane ragazza da tempo scomparsa, aiuta chiunque a disegnare. In realtà, la ragazza è chiusa per sempre nella foresta senza tempo dall'unicorno che la portò via prima che morisse di malattia per farla restare immortale.
宿題の絵が描けない優は、みどりからある森へ行けば上手に描けると教えられる。幸福の森と呼ばれるその場所は、13歳で行方不明になった天才少女画家、中原美也が最後に訪れた地だった。優は森から異世界へ迷い込み美也と会う。一緒に帰ろうという優だが、突如現れたユニコーンがそれを邪魔する…。