“I won’t have sex with you anymore.”

A long-time sexual partner is about to end their relationship. I can’t do this kind of relationship where I only have sex with the person I have a crush on.

It was late at night. The old-fashioned doorbell echoed through the run-down building, ringing on and on. Worried the noise might disturb the neighbors, Jee Heejin carefully opened the front door to see what was going on. “Who is it…?” “Hey… long time no see.” Jee Heejin and Jee Hyunwoo, who once lived as step-siblings for five years after their parents’ remarriage, meet again after five years apart. Now a handsome medical student returning in triumph, Hyunwoo approaches the drunken Heejin and whispers that this time, they should become family not as siblings, but as husband and wife… and in this forbidden reunion, Heejin is forced to make a life-altering choice.

Rohshan Owin believes he has lost his mind. He has abandoned the pride of his count’s family and the duty to carry on his bloodline, all because he is addicted to his forbidden relationship with the slave Kyle Blackburn. As the Black Dragon Festival approaches, Kyle grows more desperate. He wants Rohshan’s confession before the ceremonial Nest Marriage, and he does everything he can to provoke, tempt, and unbalance him. The longer Rohshan hesitates, the more Kyle’s patience fractures, his longing twisting into something dangerously close to madness. “Just how long am I supposed to wait? At this rate, I’m going to lose myself completely.” Within Rohshan’s mansion, secrets pile up, the suspicious deaths of his parents, the dark origins of his own unruly nature, and the true identity of the slave who has stolen his heart. Caught between obsession, guilt, and a love that refuses to stay hidden, Rohshan must decide what he is willing to sacrifice before everything collapses.

Do you ever truly know the people around you? The lives they lead, the jobs they do, the emotions they feel? Unknown Caller explores three sweet-yet-spicy tales of romance, intrigue, and drama, showing that sometimes it’s the unknown that’s the most rewarding.