Youko Kaji is a blonde-haired, blue-eyed high school student embodying typical teenage traits. As a classmate of Yuuta Yamauchi, she becomes the object of his interest. During an encounter beneath cherry blossom trees, a sudden gust of wind lifts her skirt, prompting Yuuta to photograph her in a compromised moment. This image gains significance when discovered by Yuuta's cousin, Kei. Kei mocks Yuuta's infatuation, leveraging the incident to initiate a physical relationship with him. Youko Kaji acts solely as the catalyst for this development, with no further participation beyond the initial event.