Banished from the palace as a child, Aiden finds refuge in the mysterious and powerful Graham family. Rebecca, the cold and stern heiress of the Graham family, rescues Aiden but places him in her care as her loyal instrument—a “dog” who obeys her every command. Under Rebecca’s steely gaze, Aiden undergoes rigorous training that molds him into a fierce and merciless protector. But amid the brutality of this new world, their relationship slowly changes, sparking a tangled mixture of devotion, passion, and hidden desires that they can only express in the dark. The two are caught in a tension between power and ardent desire, with Aiden yearning for Rebecca not just as a master, but as a closer, more intimate being. But the dark secrets of the royal family begin to threaten their intimacy, forcing Aiden to choose: will he remain loyal to Rebecca or fight for their freedom? Amidst the spice of love, betrayal, and hidden desires, Aiden and Rebecca face moral and emotional limits, ready to make sacrifices for each other—or drown together in unspoken desires.