Synopsis
A worldwide criminal syndicate known as Heugsahoe exists. Their boss is Choi Hee-gon.
In 2008, the leader of the Intelligence Investigation Team of the Maritime Police, Kwon Jung-ryool (Lee Sung-jae), forms a secret investigation team to capture crime boss Choi Hee-gon. As Jung-ryool gets closer and closer to capturing Choi Hee-gon, Jung-ryool's wife Min-jung suddenly goes missing. Her dead body is then thrown in front of Jung-ryool. Soon after, other family members involved in the undercover operation are killed.
Sun-woo (Choi Siwon) goes undercover on Jung-ryool's orders. Sun-woo can't stop the mission, even though there's continuous threats on his life. Soon, a policewoman who investigates Sun-woo is killed. It's clear that the woman's murder was committed by crime boss Choi Hee-gon, but evidence is still lacking for his arrest. Finally, the undercover operation is abandoned.
3 years later, Jung-ryool appears obsessed with his job, trying to forget the guilt he feels over the death of his wife. With the help of Hyun Hye-jung (Jin Hee-kyung) and a director of the maritime police, Jung-ryool forms another special investigation team. To avoid the attention of others inside the maritime police and crime boss Choi Hee-gon, the special investigation team is disguised as the #9 investigation team which is responsible for unsolved cases.
Sun-woo has been demoted to the country maritime police office in Gunsan City. There, Sun-woo busts an illegal trafficking organization and runs off with their smuggled goods. Sun-woo now becomes a fugitive. This was part of Jung-ryool and Sun-woo's plan to catch Choi Hee-gon. They hope to go through middle man Jung Deok-soo, nicknamed Popeye. Sun-woo approaches Popeye with his stolen goods, but Popeye finds out the truth. Luckily, Sun-woo is saved with the help of tactical team leader Kang Eun-chul (Yunho), his former colleague.
Sun-woo now joins the #9 investigation team. Sun-woo also takes an interest in Corporal Soo-yoon (Lee Si-young). Meanwhile, Popeye kidnaps Kang Eun-chul (Yunho). The abduction of Kang Eun-chul brings back memories of the slain police officer several years earlier.
