Externally, Sebastian Moon is the capable and young assistant of Clare Alonzo; internally, he is merely the son of a nanny, living under the charity of the Alonzo family. To the outside world, Sebastian is the brother-like figure who is always by Clare’s side; but within the family, he is nothing more than Clare’s shield, a loyal servant, and a temporary comfort during his vulnerable periods. "Sebastian Moon is just a dog that the Alonzo family has raised for eighteen years." In a devastating fire, Clare, who harbored a secret crush on Sebastian's twin brother, accidentally saved the wrong person. Sebastian, fortunate to survive, found himself forever living in the shadow of his twin. "Two Alphas can never mark each other. Regardless of whether I mark someone else or not, our relationship will remain the same." Clare once warned him in this manner. Does that mean, he could also mark someone else? Clare never imagined that one day Sebastian would accept another Omega's proposal right before his eyes. Even when Clare, tormented by his vulnerable period, knelt down begging for some pheromones, Sebastian coldly observed with someone else’s mark on him. Clare's crimson eyes reflected the indifferent gaze of his former lover. The familiar tender whispers now sounded like venomous snakes tearing at his heart and lungs: "I'm sorry, Mr. Alonzo, I am someone else's husband now. I can’t help you..." Even the child they had adopted together was cast aside by Sebastian, devoid of any pity. At that moment, Clare realised that in this unequal relationship, it was only him who was truly trapped.