Mirei Watanuki’s story unfolds across chapters 12–13 of the original manga, later adapted into the OVA’s second episode. The adaptation repositioned her arc chronologically to follow the series’ introductory events, aligning it with the protagonist’s circumstances. While the OVA streamlined the source material by omitting other arcs, it retained her storyline, placing it after the initial episodes. This narrative adjustment underscores her role in contextualizing themes of interpersonal tension and concealed relationships within the series’ broader framework.