Mouse

Terrifying news of an unsolved serial killing case strikes the country, putting everyone in fear. One day, a family of four visits a camp site just to face a horrible death by this very serial killer, Head Hunter. A boy survives the ambush and later on pinpoints the prime suspect as the killer. Meanwhile, a gene test to verify an unborn fetus for its potential psychopathic characteristics is carried out on Head Hunter’s baby, and the baby’s mother has to make a choice.

Chi Kook has been found at the prison with multiple stab marks all over his body along with a message written in blood. Not long after that, Chi Kook’s watch, a present gifted by Ba Reum and Dong Koo, was retrieved at the grape farm murder site, leading Ba Reum to join Moo Chi for the investigation. Meanwhile, Bong Yi’s grandmother stumbles upon something she should’ve never found out while working as a cleaning lady for Bong Yi’s settlement money.

An hour-long live broadcast goes on air in hopes to save Han Kook. But Ba Reum sets off to a discreet journey as the rest struggle hard to find out the predator’s motive of murder. During the live broadcast, endless tip-offs and reports from former victims of the predator flood into the broadcast station. The investigation seems to progress in a positive outlook as Moo Chi narrows down the suspects. Will they be able find the murderer in time?

After getting a gunshot wound, Yo Han is in critical condition. Ba Reum gets brain surgery. But after receiving the brain surgery, he suffers from memory loss. After a year, Moo Chi is assigned to a new team that collects and organizes criminal evidence. Ba Reum starts to work for a small precinct. On his first day at work, he accidentally finds a dead body.

Ba Reum finds out about a shocking story behind his brain surgery a year ago. He’s tormented by unwanted memories that keep haunting him. Detective Ko is furious at Han Seo Joon’s remark of being saved and being at peace after accepting Christ and decides to kill him himself.

Ba Reum keeps hearing Yo Han’s voice in his head telling him to kill people. The hallucination eventually made him murder Woo Hyung Chul. When he goes to the station to turn himself in, he finds out all the evidence related to his murder is gone, including Woo Hyung Chul’s body. Bong Yi runs into Kang Duk Soo, which makes her anxious. On a rainy day, Kang Duk Soo starts making a move again.

The DNA result found on the weapon that was used to kill Kang Duk Soo confuses Moo Chi. Bong Yi joins Hong Ju’s team and starts investigating the Suseong serial murder case. With Ba Reum, Bong Yi begins to find the link between the Suseong serial murder cases and the Guryeong attempted murder case. At the same time, Moo Chi also looks into one of the inmates’ cases from Moojin Penitentiary.

Ba Reum starts to remember everything and is filled with guilt. When Ba Reum sees Han Kook’s mother desperately looking for her child even after a year, he decides to confess his crimes and clear Yo Han’s name. Meanwhile, Moo Chi notices that Chi Kook is lying and that he reacts strangely sensitive towards Ba Reum.

Ba Reum finally remembers what exactly happened to his family. He tries to set a trap to catch the mysterious OZ, and he finds out a secret about Dr. Daniel Lee in the process. Meanwhile, Moo Chi finds the unregistered car the OZ, the murderer who killed Chi Kook, used.

Moo Chi and Bong Yi get closer to the truth. In the meantime, Ba Reum tries to find his aunt, the last missing puzzle piece. Sang, who tries to confirm Ba Reum’s alibi, finds something suspicious at Ba Reum’s house.