Mochizuki Kotaro is a mild-mannered, unmanly high school student. One day, he visits a library and meets the mysterious librarian Himiko, who recommends to him an ancient book about a heroic general from the Sengoku period 400 years ago. Kotaro notices that he has the same name and age as the general described in the book, and he experiences a flashback... Kotaro later mentions the book to his father, who tells him
