Jung Gyu Seok, secretary to the president of Poongil Industries, and Lee Kyung Hee, wife of President Kim Hwa Dong, are murdered. Kim Young Gu, an associate of Choi In Deok and Yoon Kyung Sun, kidnaps Kyung Jung, Kyung Hee's younger sister. Inspector Jo and Detective Min arrest and interrogate Min Jung Sik, Kyung Hee's ex-husband, on suspicion of murder, but find no evidence against him. Min Jung Sik, knowing Kyung Hee was having an affair with Gyu Seok, had been blackmailing Gyu Seok for money. A woman arrives at President Kim Hwa Dong's office with a baby, and Hwa Dong stabs her before fleeing. Jong Soo, Kyung Jung's boyfriend, takes the woman to the hospital for treatment and learns she is Hwa Dong's ex-wife. The woman had given birth to Kim Hwa Dong's child and, while searching for him, discovered he had married Kyung Hee. Believing Gyu Seok, who promised to reunite them, she confided all of Kim Hwa Dong's secrets to Gyu Seok, namely that Hwa Dong was a spy from the North. Hwa Dong, knowing Gyu Seok had learned his secret, planned to have his smuggling ring kill him. On the day of the incident, as the smugglers were killing Gyu Seok, Hwa Dong, enraged by his wife's affair with Gyu Seok, shot and killed his wife and kidnapped Kyung Jung, whom he had long desired. As the police net tightened, Hwa Dong, fleeing with the smugglers, got into an argument with Choi In Deok, the smugglers' second-in-command, and was killed by him. Choi In Deok shouted that he had killed a spy before collapsing, hit by a bullet fired by Hwa Dong.