Serizawa Kaho stands out with her striking green hair, blue eyes, and pale complexion, often dressed elegantly in dresses and hats. She lives a sheltered life as the wealthy daughter of a renowned painter, residing in a large hillside mansion with her father and a maid. This privileged upbringing leaves her unskilled in household chores and cooking.

As president of the drama club, Kaho commands widespread admiration at school for her intelligence, grace, and kindness, making her one of the most popular students. Despite this popularity, she exhibits pronounced shyness around the opposite sex and reacts with discomfort to physical contact. She values decisiveness and strength of character, reacting negatively to perceived cowardice or indecision. Her strict father imposes rigid curfews and restrictions, limiting her social activities and contributing to her unhappiness, though she avoids confronting him.

Initially unapproachable to protagonist Makimura Koutarou, especially after he has a friend deliver a love letter instead of confessing directly, Kaho's attitude shifts due to unforeseen time travel events. Koutarou experiences a future where they develop a romantic relationship, revealing her tragic death in a car accident at the end of summer vacation. Preventing Kaho's fate becomes the central focus of Koutarou's efforts to alter time. While Kaho is the primary romantic interest, the narrative allows for alternative relationship paths with other characters.