In an attempt to punish some mice, Maya makes a potion that is supposed to shrink things, but instead it makes things grow bigger. To make matters worse, Ruru, her familiar, accidentally drank some of it. Now she is growing larger and larger by the minute. Nina must try to hide Ruru while Maya works on getting the dispel magic. While Nina helps Maya hide Ruru, Ayu distracts the class with foolish behaviour, once again ruining her image in front of Kaji.