A car explodes in the middle of the city and kills a person. The cause of the explosion is unknown. Cha Jae Hwan, a detective from the Violent Crimes Unit, notices something strange at the scene.
Jae Han gets greeted by Reporter Kim Hyo Kyung at the hospital, and Captain Han realizes that the incidents occurring now are related to the Chimera Case from 35 years ago
After Ju Seok's death, a special task force gets formed. Jae Hwan gets interrogated for being at the crime scene, and he tells them that the water caught on fire. However, no one believes him.
Without an attorney at his side, Joong Yeop agrees to get questioned by the police. Jae Hwan tries to get him to talk but ends up losing his temper. With Eugene's interrogation, he skillfully avoids answering any questions.
Seoryun Medical Center's legal team stops the police's interrogation of Joong Yeop, the main suspect, and he is free to leave. Now safely at his house, Joong Yeop recollects what happened at the Macheon Police Department when he was young.
Jae Hwan and Eugene question Lee Sang Woo's death 35 years ago. As they dig into the case file, they come across Bae Seung Kwan's name, the current chief of police. Slowly, the truth behind what happened 35 years ago becomes revealed.
Jae Hwan tells Captain Ko Gwang Soo that Hahm Yon Bok was in charge of the Chimera Case 35 years ago and shares his suspicions surrounding Lee Sang Woo's death. Meanwhile, another explosion takes place.
After the explosion, Hyo Kyung from UBS Newsroom visits Eugene at her office. She tells her that she believes the Chimera Case from 35 years ago is related to the current incidents.
Jae Hwan asks Chief Bae why Hahm Yong Bok got discharged 35 years ago, but Chief Bae becomes defensive and doesn't give him an answer. Meanwhile, Agent Hathaway finds suspicious things about Kang Sang Gu and keeps a close eye on him.
Kang Sang Gu is taken in as a suspect of the Chimera Murders. Solid evidence is found at Sang Gu's home, and he confesses to all the murders he committed as the Chimera. Something however, tells Jae Hwan that the case is not over yet.
Jae Hwan learns that his mom's memories from before the accident are coming back. Later on, Jae Hwan is told that Joong Yeop quit his job at the hospital and left the country.
Joong Yeop turns himself in, and is taken to a remote mountain by the prosecution. He is made to walk deeper into the woods at gunpoint until they arrive at a cliff. A suspicious package is delivered to Chief Bae's office
Joong Yeop takes control of the situation and flees the scene from the prosecution. As the police chase him down, a secret message is sent to Eugene. She and Jae Hwan meets with Joong Yeop. Jae Hwan and Joong Yeop have a tense moment.
Hyo Kyung calms Joong Yeop, and she learns about the whole truth behind the Chimera Case that happened in the past. When Hyo Kyung meets Joong Yeop again, she notices a tail. As Jae Hwan rushes to help him, a bullet strikes Joong Yeop.
Jae Hwan discovers that the bullet found at the crime scene was not police issued. He then rushes off to see his mother, who is now under supervision. Kim Hyo Kyung appears on an internet show and reveals new facts about Chimera.
Jae Hwan goes to the broadcasting station to find Hyo Kyung, but he hears that she has already resigned from her position. When they finally come face-to-face, she already seems to have an ending in mind.
