Yamada Hana is just an average student. One day, when she reads a book about the Romance of Three Kingdoms, she is suddenly surrounded by a flash of light and she loses consciousness... When she wakes up, she finds herself in a forest. A man appears in front of her, and she is at a loss of what to do. The man's name is Koumei and she meets another person called Gentoku, but she is mistaken for a disciple of Koumei's and ordered to command an army and take part in a battle... She doesn't know what to do, but somehow she wins the battle...