Misora Takatsuki, a high school freshman, is struggling with a major challenge: her height. Despite being 15 years old, she is often mistaken for an elementary student due to her petite frame. Although her friends lovingly tease her, it only adds to her lack of confidence. To top it off, Misora's younger sister Kotori, who is just 11 years old, seems like she could easily pass as a high schooler. Although Kotori looks up to her sister and seeks her attention, Misora feels uneasy about the unexpected role reversal in their sibling dynamic.