It is revealed that Saya's father works as a doctor and while at work overseas, she was taken with him and she was given a manga which she treasured dearly. When she returned to her hometown, she meets Riki and they play ball together until it starts to rain. On the way home, a mudslide seemingly kills Saya, but not before she enters the artificial world Kyousuke created. She is repeating the same scenario, and dies every time, thus making Kyousuke rewind time. In one of the replays, Saya and Riki face Tokikaze Shun, the antagonist of the manga Saya loved so much, which, coincidentally, Saya is the protagonist of the same manga.
地下迷宮の奥深くに眠る「秘宝」とは何なのか——。理樹と沙耶はまだ見ぬ「秘宝」に思いを巡らせ、戦いが終わった後にデートをしようと語り合う。だが、その前に最後の決着をつけなければいけなかった。ふたりの前に立ちはだかったのは、闇の執行部部長・時風瞬。この迷宮の支配者であり、何度戦っても勝ち目がないほどの強敵だったが、沙耶には策があった。切り札である理樹を使って、沙耶は「ラストゲーム」に挑む。
