Tsugumu Ichimonji, a world-renowned high school bodyguard, transfers to a Japanese high school to secretly guard Himeru Kokoro, the daughter of a wealthy man. One day, he chases her to the rooftop and witnesses Himeru, a huge dragon and a flame all around her!! "Don't worry... I'm immune to fire!" Himeru Kokoro is the reincarnation of a hero from another world. If the secret is leaked, the world will be in danger! Tsugumu Ichimonji vows to protect her secret, but there is not just one secret he needs to protect. On the contrary... Her secret inevitably opens the door to the extraordinary.