Sketch - Season 1

Kang Dong Soo, a detective, dreams of living a happy life with his fiancée. However, another detective, Yoo Si Hyun, who draws sketches of crimes that occur within 72 hours, predicts Dong Soo's fiancée's death. Dong Soo and Si Hyun work together but they are running out of time and clues for their investigation to prevent the crime.
 

In order to prevent the future from being unfold according to the sketch, Dong Soo and Si Hyun look for clues together. They track down the culprit and find Ji Soo's car at the same place. When Do Jin falls in despair, a mysterious man approaches him.

Dong Soo is determined to catch the guy who killed Ji Soo. Meanwhile, Do Jin is given another target to kill. In order to pursue the man who killed Ji Soo, Dong Soo gives up his badge and goes rogue.

Dong Soo is shocked when he finds out that Do Jin is the one who killed his wife. Do Jin hears from Tae Joon that it was the decision Dong Soo made that ultimately led to the death of his wife. Meanwhile, Si Hyun finds herself in the sketch she has drawn.

Dong Soo and the Nabi Team members try their best to find Si Hyun. However, they aren't able to find a clue while the time keeps flowing. Meanwhile, Si Hyun tries to escape from Il Woo and his crews. Il Woo suspects that someone is tailing him, so he orders his men to kill Si Hyun.

Dong Soo appears in time to save Si Hyun. Dong Soo chases after Il Soo, who tries to escape, and meets Do Jin. The unknown people get off from a mysterious car and kidnaps Do Jin. Dong Soo decides to join hands with Sun Woo to earn what he wants.

Dong Soo and Do Jin get caught in Sun Woo's trap. In a moment of life and death, Do Jin tells Sun Woo that he has a gift for him and tells him to open the bag. What Sun Woo finds in the bag is a bomb with only seconds left. The scene becomes chaotic as the bomb goes off. When Si Hyun arrives, it is the exact scene in which her death was predicted.
 

Dong Soo deducts that there may have been a man who used to do the things that Do Jin is doing now. While looking for that man, the team finds a detective named Baek Woo Jin. The team gets one step closer to the truth from what they hear from him.

Nabi Team members get shocked as they believed Tae Joon could foresee the future. Woo Jin tells Dong Soo that Tae Joon's notebook is the key to find out who is behind Tae Joon. Si Hyun gets to sneak into Tae Joon's office and manage to get his notebook. However, as Si Hyun steps out from the office, she faces a detective.

Prosecutor Yoo joins in the investigation and personally visits Kang Do Sik's house, who is responsible for Si Hyun parents' death, and as a result, finds himself in the hospital. Si Hyun sketches a picture that's identical to the scar Prosecutor Yoo gets from a chase and later finds out Kim Do Jin is behind his kidnapping. She heroically saves her brother moments before Detective Kang loses his chance to arrest Kim Do Jin.

Si Joon reveals himself to Do Jin. Do Jin gets shocked as the unexpected person shows up. Meanwhile, Dong Soo and Si Hyun look for the wife of Pil Gyu, who ordered Do Sik to steal Si Hyun's father's notebook. Pil Gyu's wife tells Dong Soo and Si Hyun that another person came by to ask about the incident that occurred 20 years ago. Dong Soo feels that this incident is related to Ji Soo's death and looks for the USB.

Moon Gi feels thankful towards Tae Joon for saving his life. However, Moon Gi is suspicious of Tae Joon as he does not request for anything in return. Nabi Team believed that Jung Yeon is the Elder, but they get devastated when they find out that Jung Yeon is not the Elder. Meanwhile, Si Hyun starts to draw another sketch and finds a drawing that shows someone's death. Who could it be?

Yoon Sung Soo, who knows about the X, wakes up. Sung Soo offers Nabi Team to bring his son if they want to know about what he knows. To earn the evidence, the Nabi Team members go around everywhere to find Sung Soo's son. Meanwhile, Moon Gi feels suspicious about Si Joon and Tae Joon's relationship. Moon Gi orders Mr. Choi to find out about Si Joon.
 

Si Joon knows the story that Jae Hyun had only told Dong Soo. Dong Soo thinks Si Joon has killed Jae Hyun. Dong Soo asks Young Shim to keep it secret from Si Hyun. They start to look into Si Joon's background. Dong Soo and Young Shim find out Tae Joon and Si Joon's relationship had started from the fire incident at Seosu Building. Nabi Team finds Do Jin's hiding place and sees Mr. Choi locked up inside.
 

Tae Wook tells Si Hyun that Si Joon had killed Jae Hyun. Although Si Hyun can't believe Tae Wook's words, she decides to take Tae Wook to the Joongki Police Station. Tae Joon goes to the police station to take away Tae Wook. However, he gets stopped by Dong Soo and at last Tae Joon decides to take out his gun. Si Hyun begins her sketch and draws a shocking picture of Si Joon.

Nabi team finds out that Tae Joon and Do Jin were working for Si Joon to get rid of the Elder. Meanwhile, from Tae Joon's item, Do Jin feels extremely angry and betrayed by Si Joon. Si Joon tells his location to Dong Soo. Si Joon's foreseeing starts again. Si Joon sees Si Hyun's death at the same place as Si Hyun's sketch of Si Joon's death.