Awakening in a mysterious dungeon, Rui meets Claude, who rescues her from a monster, and realizes she has successfully transferred to another world: "The Tower of God," the setting of a popular Otome game. Another transferee, Mayu, possessed the crest that proved she was the heroine. However, Rui has neither a crest nor the ability to use magic. In order to return to her original world, Rui tags along as a burdensome mob character while being mistreated by Mayu. Amidst all this, as Rui begins to connect on a deeper level with the capture targets, the heroine's crest starts to appear on her as well...!? Displacing the heroine in a labyrinth dungeon?! A grand reversal romantic fantasy officially begins!