Princess Emeriel cuts her silver hair and smears mud across her face, disguising herself as a male slave in the brutal Beast Kingdom of Urai to protect her fragile younger sister. As a rare mythical siren, Emeriel conceals magical melodies that could ignite wars across the continent. When the fearsome Beast King Daemonikai succumbs to a bloodthirsty madness that slaughters his own royal guards, Emeriel steps into his iron cage, using her soothing voice to calm his feral rage. Stunned by the mysterious slave's ability to pacify his cursed beast, Daemonikai demands the youth serve as his personal companion, keeping Emeriel at his side day and night. But jealous royal concubines suspect the slave's true gender, setting deadly traps to expose her in public. As war threatens the kingdom and Daemonikai's desire turns obsessive, will Emeriel's secret be revealed before love can triumph?