While in pursuit of criminals, a police officer has an unexpected encounter with a rather uncanny demon. Barely surviving the incident, Do Gyeong Joon is left staring after the retreating form of the mysterious creature in bafflement. However, not long after this the two meet again when the demon crashes into Do Gyeong Joon’s apartment, saying: “Hurry up! I need to get inside of you”…!?
Kyungjoon had lost all hope for a fulfilling life after his fiancée passed away. His days were now filled with tending to his house plants and dealing with petty crimes as a police officer. But everything changed when he stumbled upon a supernatural cult that led him to encounter “Lord Cain,” a demon king on the brink of death due to a lack of mana. As it turns out, Kyungjoon’s body could serve as a “door” for Cain to enter Hell and regain his strength. However, the process of opening that door involves some NSFW activities… Will Kyungjoon take the risk for the sake of helping Cain, or will he choose to play it safe?