A herbivorous dragon who wanted to live a peaceful life met a middle school girl named Reiko. Since Reiko was determined to die, he could not persuade her no matter how he tried to persuade her, so he had no choice but to make up a lie so that Reiko could live. Under the lie made up by the "evil dragon", Reiko and the "evil dragon" she believed to be the strongest embarked on a journey to defeat the demon king's army.