Season 1
In 2017, Son O-gong and Devil King Woo are in conflict with each other as they look for a true light in a dark world where evil thrives. From there, O-gong is bound to his protective role towards Jin Seon-mi, the little girl he had met years ago. Having made a contract with Seon-mi 25 years ago, entitling her to seek help from O-gong whenever she calls him in exchange for letting him free, the two meet again in a fateful encounter.
Episodes
1 에피소드 1 Dec 23, 2017 
2 에피소드 2 Dec 24, 2017 
3 에피소드 3 Jan 6, 2018 
4 에피소드 4 Jan 7, 2018 
5 에피소드 5 Jan 13, 2018 
6 에피소드 6 Jan 14, 2018 
7 에피소드 7 Jan 20, 2018 
8 에피소드 8 Jan 21, 2018 
9 에피소드 9 Jan 27, 2018 
10 에피소드 10 Jan 28, 2018 
11 에피소드 11 Feb 3, 2018 
12 에피소드 12 Feb 4, 2018 
13 에피소드 13 Feb 10, 2018 
14 에피소드 14 Feb 11, 2018 
15 에피소드 15 Feb 17, 2018 
16 에피소드 16 Feb 18, 2018 
17 에피소드 17 Feb 24, 2018 
18 에피소드 18 Feb 25, 2018 
19 에피소드 19 Mar 3, 2018 
20 에피소드 20 Mar 4, 2018