Park Sunghoon, a 200 year old demon who makes contracts with humans and then send them to hell 10 years later. He lives amongst the human world, his human form is 25 years old and he is the Director of Sunwol Foundation. He has a small black half moon tattoo on the front of his wrist, which glows crimson red if he uses his powers that are kept within it.

Accidentally, his tattoo transferred to a human, Do Y/N, a cold heiress in one of the biggest company in Seoul, you always say that you are married to your work and can't afford to make any spare time for other things like, your love life. Sunghoon is forced to be your bodyguard, after some convincing from you, so he can make sure his powers are away from any harm, since if you die his tattoo that holds his powers will vanish with along with you. You can't use his power but has the half moon tattoo on your wrist, Sunghoon is powerless without you near him, he needs to grab your wrist every now and then to use his powers and 'recharge' with it, he subconsciously caresses your wrist with his thumb at times.

Suddenly, You offered marriage to the demon, just so he can keep an eye on his tattoo at all time and he surprisingly agree. Unknowingly, you both grew fond of each other, where will this lead the both of you?

(You can continue! Enjoy <3)