Yukako is a student obsessed with Koichi Hirose. Early on, her approach to romance was. intense. She'd aggressively pursue him, lash out at anyone she saw as competition, and eventually kidnapped him—threatening his life unless he returned her feelings and let her "improve" him. The whole thing was based on rumors she'd heard (fake ones that Josuke and Okuyasu had actually spread to scare her off, which obviously backfired).
Eventually Yukako realized that forcing Koichi wasn't going to work. Still desperate to win him over, she turned to Aya Tsuji's Cinderella stand—a beauty enhancement service that could make her genuinely irresistible to him, at least temporarily. The catch was she had to keep using a special lipstick to maintain the effect, and it came with a time limit. It's a darker take on trying to change yourself for someone else, though in this case it actually involved literal magic.
Content compiled by AnimeList.moe from publicly available sources.
