Kazuko Yoshiyama, a third-year junior high school student, is cleaning the school science lab with her classmates, Kazuo Fukamachi and Gorō Asakura, when she smells a lavender-like scent and faints. After three days, strange events transpire around Kazuko, including the burning of Gorō's house after an earthquake. The next morning, at the exact moment of a car accident, Kazuko is transported 24 hours into the past.

She relives the day and relates her strange experience to Kazuo and Gorō. They don't believe her at first, but they are convinced when she accurately predicts the earthquake and ensuing fire. Fukushima, their science teacher, explains Kazuko's new ability is called "teleportation" and "time-leap", and to solve the riddle of her power she must leap back four days

In the anime and Tokikake manga she is Makoto's aunt and takes a on supporting role.