"If I kill one murderer, the number of murderers stays the same. If I kill more than one, it lowers."

On the city island of New Arcadia, life should be better, but the underworld is very much alive and ruled by self-interest and sin.

Roselin, an eager art student, feels lost and alone when she meets the hardened mafia boss Ryu who uses his Mageía powers to benefit his needs. With every kill he makes, he gains more power over the shadows of the city, literally and figuratively.

Although their morals clash, Roselin can't help falling for him, captivated by his shadows, while Ryu is mesmerised by Roselin and her art. Can they survive together when an enemy is out for revenge?