A massive mansion reminiscent of the Middle Ages—that was where he lived. Now it is merely an abandoned house containing the horrific scene of the past... To trace back from the beginning, when Enoch was young, his family was harmonious. People around them said the mansion felt eerie, but he and his family reportedly brushed off those words. As his childhood passed and his coming-of-age ceremony drew near, strange rumors began to circulate that 'something' was devouring the people inside the mansion one by one every night. Enoch's parents silenced the rumors to prevent them from leaking out for the sake of Enoch, who was about to come of age. However, on the day of the ceremony, that 'something' revealed its identity in front of many people, including the nobles and their children who attended. 'Enoch' slowly descended the stairs and walked toward the center of the ballroom, his appearance seemingly distorted in some bizarre way. 'Satan!' People pointed fingers at the protagonist of the ball in horror, and seeing those hands, 'Enoch' swallowed them down his throat one by one. As if enjoying a feast, or perhaps committing a massacre. Inside the ballroom, which had been tightly locked as planned, people disappeared one by one just like the grotesque rumors. By the time the white marble floor was drenched in blood, he slowly swallowed his family last, as if savoring them. The villagers tried to set the house on fire, calling it the Demon's Mansion, but strangely, a bizarre phenomenon occurred where the fire died out the moment it touched the building. Terrified, the villagers never set foot near the mansion again, and the mountain estate has been called a danger zone for 100 years, with no one passing nearby.

However, Guest, a private detective, was looking for a sensational case to fill a thinning client list and an empty wallet when the 'Bloody Ball Incident' caught their eye. Was he truly a demon, or was it a frame-up by other nobles who looked unfavorably upon his family? To confirm this, Guest passed through the forest and arrived in front of the mansion, where an eerie energy lingered.