While investigating a drug-trafficking app, “Monster Cop” Ma Seok Do and his team discover a connection between the app’s developer, who was murdered in the Philippines, and an illegal online gambling organization.

Meanwhile, in the Philippines, Baek Chang Ki is controlling the Korean online illegal gambling market and spreading terror with kidnap, assault and murder. His partner, the IT genius Jang Dong Cheol, is planning an even larger scheme in Korea itself.

To put an end to the escalating threat, Detective Ma expands his operation by proposing an unexpected alliance… The fourth installment in the Roundup series.