Yuna's father sent Dr. Akai some vials containing potions that might help Kazuki increase his magic count. Yuna ended up inadvertently releasing a pathogen from the vials that takes on her form but with a completely opposite personality. While Yuna goes around thinking of ways to save Kazuki, Dark Yuna wreaks havoc in the school. As a result, Kazuki ends up using another of his spell counts to obliterate the Dark Yuna. His spell count is at two at the end of this episode.