Micca steps down to earth with a mission to search for heaven's lost precious soul—Human. He has accidentally possessed Amber's body as his vessel and couldn't get out. However, Amber's dark emotions and lustful desires create an unpredictable switch of personality between them as Micca eventually develops feelings for her. On the other hand, Amber is unaware that she is being possessed by an angel. With the guidance of Gideon and an hourglass that limits his time on earth, Micca continues his search for Human without knowing that Amber and Human are one. Would Micca ever find out that Amber is the lost soul that heaven is looking for before it's too late? Will he succumb to a forbidden kind of love that could turn him into a demon?