In 2017, Son Oh-Gong and Ma-Wang are in conflict with each other as they look for a true light in a dark world where evil thrives. Having made a contract with Seon-mi 25 years ago, entitling her to seek help from Son Oh-Gong whenever she calls him in exchange for letting him free, the two meet again in a fateful encounter. From there, Son Oh-Gong is bound to his protective role towards Seon-mi, the little girl he had met years ago.
CEO of Lucifer Entertainment. A gentle and charismatic businessman, he is the object of others’ envy due to his popularity. He has a bad history with Son Oh-gong in the past, and now seeking for chances to be a deity through 'collecting' points in order to change the fate of the woman he loves.
A real estate CEO who resells houses that have had notoriously bad luck (inhabited by evil spirits). She is wealthy, beautiful and has an unyielding tenacity. When she was a kid, she was ostracised by her peers. She meets Ma-Wang, and releases Son Oh-gong from his prison, and later meets him again by fate. Son Oh-gong is the love of her life.
Two spirits in a body whereby General Dong is Son Oh-gong's advisor who owns an ice cream shop in the day whilst Fairy Ha is a warm and social lady who owns a cocktail shop in the night, offering a listening ear to the demons as well as Sam-jang.
Park Bo-gum was offered the lead role of Son Oh-gong in July 2017, but eventually declined.Choo Ja-hyun was originally cast in the cameo role of Na Chal-nyeo, but had to be replaced by Kim Ji-soo due to pregnancy.
According to data released by Nielsen Korea, A Korean Odyssey ranked the most-watched show of its time slot including both cable and public broadcasting channels for its premiere episode. Moreover, the series broke the record for the highest ratings for the first episode of a tvN drama in the Nielsen Korea 20-49 year-old target audience bracket.
On December 24, episode 2 broadcast was repeatedly interrupted by long commercial ads during which tvN displayed a message stating that there are "internal issues delayed the broadcast". The broadcast then resumed but then was later abruptly cut altogether. tvN issued an apology stating that there was "a delay in the computer graphics process" and that "the finalized version of episode 2 is set to air on December 25 at 6:10 p.m. (KST)."
The show suffered another controversy when it was revealed that a staff member was seriously injured after falling on set.
In the Philippines, the show started airing on July 9, 2018, under the title Hwayugi: A Korean Odyssey on ABS-CBN's Primetime Bida timeslot at 9:55PM PST, replacing their Korean drama Doctor Crush. The drama is dubbed in Filipino.
^On December 24, 2017, episode 2 did not fully air due to "internal issues" and was re-broadcast the following day at 18:10 (KST).
^Episode 3 and 4, which were supposed to air on December 30 and 31, 2017 respectively, were pushed back a week to give time for the production team to work on the CG, as well as to evaluate the production process of the program.