"Did I take away their lover?" Seo Ino, an average man from South Korea, wakes up after losing consciousness to find himself in a strange place. He soon comes to the realization that he is inside the body of Cassius, the Vice Captain of the Royal Knights. The only person he can rely on is Cassius's fellow knight and former lover, Alberto Noe, who has always protected Cassius. But knowing that Alberto is all he has now, Cassius (Ino) makes a vow to protect him instead.