Through the schemes of the Great Divine Spirit and Seol Ji-han, the head of the Black Tortoise Clan, the Azure Dragon Clan is wiped out overnight.
Determined to avenge his fallen clan, its leader, Eun Do-hyun, takes up his sword against the two masterminds. Instead, he is captured.
As if that weren't bad enough, he becomes bound to his greatest enemy, Seol Ji-han, by an unbreakable master-servant contract.
"You're my servant now. A servant doesn't argue with their master."
"Seol Ji-han... Even if it costs me my life, I will never forgive you!"
Although Seol Ji-han is the enemy he longs to kill, Eun Do-hyun cannot deny that he is gradually being drawn to him.
And as time passes, he begins to notice something strange about Seol Ji-han's mysterious actions...
