Dentsu Meitetsu Communications

Nobumasa Tsuboi (Yo Oizumi) runs a small factory in a small town. He has a daughter Yoshimi Tsuboi (Riko Fukumoto) who suffers from a congenital heart disease. A doctor tells Nobumasa Tsuboi that his daughter will only live for about 10 more years. Nobumasa Tsuboi is devastated that his daughter won't live past the ago of 20. Nobumasa Tsuboi and his wife Yoko Tsuboi (Miho Kanno) cannot accept the diagnosis. Even though he has no medical knowledge or experience, Nobumasa Tsuboi begins to study about artificial hearts.

Students, including Aoi Nishino, take part in class and sports activity at a prestigious high school. Aoi Nishino is a member of the school's archery club. He practices archery studiously and doesn't socialize much with the other students. His childhood friend Haruka Seno is also a member of the archery club, but she worries about Aoi Nishino. One day, thunder strikes the school grounds. After that, the ordinary lives of the students changes drastically. Many samurai descend on the school grounds. It appears that the entire school has traveled back in time to the Sengoku period. Making things worse, they realize that they are in the time right before the Battle of Okehazama takes place.