It is April 1918. Spring is in the air. On his way to meet his fiancé in an arranged marriage that was worked out before he was even born, Second Lieutenant Ijūin Shinobu comes across a girl riding her bicycle with her red ribbon flapping in the spring breeze. She goes by the nickname "Haikara-san," meaning "Miss Modern," but her real name is Hanamura Benio. This girl who appears all of a sudden like a whirlwind before Shinobu is in fact his destined partner.