Lee Ahn (Jinyoung) is a boy with an incredible power to sense other people's secrets just by a simple touch. Yoon Jae In (Shin Ye Eun) is a girl who'll stop at nothing to hide a traumatic secret. What will happen when their worlds collide? A romantic thriller about how these two teenagers love, heal, and support each other through big and small events.

Lee Ahn (Jinyoung) is a boy with an incredible power to sense other people's secrets just by a simple touch. Yoon Jae In (Shin Ye Eun) is a girl who'll stop at nothing to hide a traumatic secret. What will happen when their worlds collide? A romantic thriller about how these two teenagers love, heal, and support each other through big and small events.

The math teacher who got fired because of Jae In uncovering the truth tries to retaliate. An appears at the right moment to save Jae In and he continues to stay with her to protect her. However, the secret Jae In wanted to hide from everyone has been revealed and she disappears.

After two years, An and Jae In meet again. Jae In has become a police officer while An doesn’t seem to have made much progress in honing his psychometry skills. While they are both trying to find a kid that went missing, An finds a suspicious suitcase that turns out to have a dead body in. Will the two be able to find the killer?

Seong Mo asks Jae In to help improve An’s psychometric powers. While Jae In hesitates to let An perform a read on her, An realizes that she’s the girl he remembers from long ago. Meanwhile, Dr. Hong identifies the body found in the suitcase, and while following Seong Mo, An meets a mysterious man.

As Seong Mo wished, Jae In promises to help train An’s abilities. As An is discharged from the hospital, he and Jae In start to read books on crimes. To find more information on the real Kang Hee Sook, Ji Soo calls An and Jae In to the autopsy room.

An realizes his ability can improve and help others only if he challenges himself. Slowly but surely, he is making efforts to change. With An’s ability, Seong Mo and Ji Soo identifies the killer and gathers information on his gang. They plan to raid the gang’s headquarter, but gets denied for not presenting evidence or witness.

An and Jae In gets caught after infiltrating Dragon Head Hunting. Soon after they fight their way out, the police raid the building with overwhelming manpower. After a successful raid and interrogating the thugs, Ji Soo and Seung Mo realize this case is bigger than they imagined.

Dr. Hong and Ji Soo discover something strange from the autopsy of Kang Eun Joo. Moreover, they are shocked that the composite sketch of Kang Hee Sook looks like Eun Joo. Meanwhile, An and Jae In go on a first date. With his unusual ability, An accidentally finds out that Jae In’s father was the culprit of the arson at Yeongseong Apartment.

An is terribly shocked to know that Jae In’s father was the arsonist of Yeongseong Apartment fire, and he runs away from Jae In. Ji Soo strongly believes that Seong Mo’s mother is still alive and is now living as Kim Song Hee. However, Ji Soo doesn’t understand why Seong Mo keeps it as a secret to her. Meanwhile, the security camera around the security center is down again, and Jae In runs into a suspicious man.

Jae In is kidnapped by a mysterious man who looks familiar to her. Although the police have his picture from the security camera footage, they still can’t catch him. Seong Mo disappears and Ji Soo keeps tracing where Eun Joo is and finds out that she attempted suicide on the day she made a briefing about Kim Gab Yong and the two victims. Meanwhile, Ji Soo investigates Eun Joo’s background and is about to dig out Seong Mo’s awful childhood.

Ji Soo, together with Jae In and An, go to where Eun Joo first lived and find out her and Seong Mo’s painful past, that they were trapped in a basement with shackles for nine years. Besides, they also find out that Yeongseong Apartment fire, Hanmin Care Home fire, the murder of Kim Gab Yong were all committed by Kang Geun Taek, the man who confined Seong Mo and Eun Joo and abducted Jae In. However, there is another cruel truth awaiting Ji Soo.

An finds out that Seong Mo knew Kang Geun Taek was at Kangguk Station and that he sent An and Jae In to somewhere else to save their lives. An keeps blaming himself. Meanwhile, Eun Joo is questioned by the police. She starts to talk everything she remembers from the Hanmin Care Home.

An tries to make Eun Joo talk again, but he fails to get anything from her. Meanwhile, the police find surveillance camera footage of Seong Mo. According to the footage, they start to track Seong Mo. Jae in and Lieutenant Nam head to a hospital where they believe Geun Taek is confined.

An sees in his vision that it was Seong Mo who framed Geun Taek to protect his mother. Found at Unit 1501, right before his arrest Seong Mo confesses to An about everything. Seong Mo admits all of his crimes and even hands out the ledger he had that includes all bribery behind YSS Construction and high authorities. Jae In, An, and the whole Investigative Unit come together to finally put things back to where it should be.