In South Korea, a serial killer nicknamed The Shadow Killer is spreading terror throughout the country. He is responsible for numerous murders, but no one yet knows the real reasons that push him to commit these acts.

The investigator responsible for finding and arresting this criminal is Hwang Jiho, also known by the nickname Jin Beau to professional investigators and police officers.

While Jin Beau conducts his investigation to put an end to the massacres, the killer prepares a particularly morbid game for him. If he decides to continue the investigation, he will have to pay the price. But The Shadow Killer doesn't plan to kill him or resort to physical violence. His main weapon will be psychological manipulation.

The criminal makes Jin Beau believe that he is holding his family hostage: his wife and daughter. From now on, the investigator finds himself trapped in a psychological game in which he can no longer trust anyone.

Before it's too late, Jin Beau will have to discover what is true and what is false, unravel the criminal's lies and solve this investigation. He only has nine months and sixty seconds to discover the truth. After this period, his family will be condemned.