When a crime organization from North Korea crosses borders and enters South Korean soil, a South Korean detective must cooperate with a North Korean detective to investigate their whereabouts.

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.