Seven years after the roundup in Vietnam, Ma Seok-do joins a new squad to investigate a murder case. He soon starts to dig deeper when he finds out the case involves a synthetic drug and a gang of thugs.

Follows Rim Chul-ryung heading back to South Korea in pursuit of a brutal and secret criminal organization. He teams up again with Kang Jin-tae, who volunteers to work with the North Korean in order to get back on the investigation team after a mistake landed him in the cyber crime department.

After the death of an unknown uncle, a woman inherits a burial ground and finds herself in the center of a string of murders and dark secrets.