Kisaragi and Yayoi, sisters who lost their parents in an accident at a young age, were placed with different relatives and raised without even knowing of each other's existence. While Kisaragi was raised like a true daughter, Yayoi was taken in by an elderly man named Mamiya to settle a relative's debt and is now set to marry him. Upon receiving a letter from the old man and learning the truth, Kisaragi travels to Tokyo, determined to call off the marriage and take her sister in—but...