Mizuki comes to Tokyo to take an entrance exam. She ends up staying with her aunt. Her aunt lives with her older cousin Mizuki. Mizuki only met and played with Misuzu a few times as a child, but hasn't seen her for over 10 years. When she meets her cousin Misuzu again after a long time, she finds that she has become a fully grown adult. Mizuki stares intently at Mizuki. Before she knows it, Mizuki begins to become aware of Misuzu. And then...