Hwawon-guk, the country where only very few powerful females are born wearing a "flower" on their heads. Amongst them, only the "flower who possesses divine powers" becomes the Emperor.

In order not to be sentenced to death with the charge of treason by "attempting to overthrow the Emperor with a new Flower", eleven-year-old Kang Wi, as if he is being bartered away, gets betrothed to the five-year-old Crown Prince, Moran the Fifth. Although Kang Wi is determined to protect the Crown Prince, the Emperor calls off the pair's engagement within two years of his decree, as if poking fun at the young child's resolve. Kang Wi is then sent back to the northern borders to fend the country against a foreign invasion by a country in the North.

Thereafter, with the sudden passing of Moran the Fourth, the Emperor who ruled with an iron fist, Kang Wi returns back to the palace after thirteen years. There, he is reunited with his ex-betrothed and the current Emperor, who now has a different hair color and the peony on his head having disappeared.

Moran the Fifth is able to use "divine powers" despite being a "butterfly" who, very evidently, did not have a flower on his head. This strange phenomenon is entangled with the tales of the founding of the country, of which "a certain truth" has since been lost with the spreading of the legends through word of mouth... Will Moran and Kang Wi be able to unravel the truth, while resolving issues that come with politics in the palace as well as a foreign invasion by the country in the North...?