The mystery of the Manor on top of the Joe-eu mountain would have forever been an enigma to the Joe valley people if not for Kim Taehyung, the explorer. Who had not only climbed up the mountain and came back in one piece but also claimed before all the village people that he had seen a young man, alive and kicking, on the mountain. But the people found it hard to put their trust on someone who, himself, had forgotten how he ended up in the village in the very first place when he was on the mountain with that young man last night? Kim Taehyung is agitated when when no one believes him. So to prove that the man he had seen is no hallucination but a real human, Taehyung decides to climb the mountain again to unveil the mystery. Taehyung has questions that only the mysterious man on the mountain can answer. But what Taehyung doesn't know is that he is looking for a man who is non-existent to the world to exist on the Mountain Of Sins. And Taehyung is entering a world, which he can enter on his will but leave only when the Mountain Of Sins allows.