It absolutely baffles me when shows like this get rated below a 7, whereas other completely mindless, horribly written ones with atrocious dialogue and acting get much higher ratings.
Albeit no "Train to Busan," most of Yeon Sang-ho's works post that blockbuster were all compelling in their own rights. Hellbound tackles the issue of religion and the dangers of cultish behavior, Jung-E is a family story packaged in an action drama, and this one, once again tackles familial relationships but in a much different arena. And there's always something humane at the core of these shows that grounds them, despite some of the outlandish scenarios. What happens when absolute devotion to your family pushes you to do irrational things; what happens when lack of devotion creates similar outcomes? This is a wonderful exploration of the complexity of what family means, should be, could be, shouldn't be, is expected to be, etc.
The acting is superb, and the characters are complex and dynamic. Highly recommended.