‘Dr. Brain’: Episode 4 Recap – Sewon Revisits Where the Tragedy Happened

In Apple TV+‘s Dr. Brain Episode 4, Koh Sewon (Lee Sun-kyun) gets closer and closer to finding more clues about what happened to his son. Since episode 1 of the Korean drama, Sewon uses the memories of the dead through brain syncs to unravel the mystery that has ruined his family. Episode 4 reveals the shocking truth behind Sewon’s death and who is could be behind the bigger picture yet to be fleshed out.

[Spoiler alert: This article contains spoilers about Dr. Brain.]

Character Koh Sewon from 'Dr. Brain' Episode 4 looking at a piece of paper.
Character Koh Sewon from ‘Dr. Brain’ Episode 4 | via Apple TV+

Sewon painfully goes back to the location where his son died in ‘Dr. Brain’

Junki’s (Kim Joo-hun) daughter drew a butterfly for Sewon with a possible clue to what she knows about his son in episode 3. At the beginning of Dr. Brain episode 4, Sewon tells Jiun (Seo Ji-hye) there is something strange about the drawing. His son died in the summer, but the drawing has fall leaves. Jiun thinks is inaccurate but Sewon says his son only met Junki’s daughter a few months ago and she is a gifted child. In the car, Jiun tells Sewon he is still a murder suspect and will be under observation.

Sewon asks Jiun to look for Namil (Lee Jae-Won). He was meant to meet with him at the mall and likely saw the face of the hitman that got away. In an undisclosed location, fans meet Secretary Yoon (Yoo Teo) talking to the hitman and telling him to find Namil. Back at home, Sewon visits his wife and is troubled by the drawing. Kangmu (Park Hee-soon) appears and urges him to go to the cabin where Sewon last saw his son.

Jiun learns Sewon left his home and has the police follow him. Jiun’s partner asks Namil’s coworker, Yoo-Jin (Ahn Mi-na), if she has seen him, which she denies. The episode shows a flashback of Sewon telling his wife he cannot go with them to the cabin like he promised, upsetting his wife. Sewon arrives at the cabin that has been burned to a crisp. Memories show Junki and his daughter accompanied Sewon’s wife and his son to the cabin instead.

‘Dr. Brain’ Episode 4 reveals what really happened at the cabin

RELATED: ‘Dr. Brain’: Episode 1 Complete Synopsis and Breakdown

Back in the city, the hitman visits Namil’s mother for information about his whereabouts. He knocks her unconscious when she lies. At the same time, Secretary Yoon breaks into Sewon’s house and disconnects his wife’s breathing tube. But when he receives a text from someone named Dr. M, he reconnects it and leaves. Viewers are then introduced to Taegu (Um Tae-goo) memories.

He and the hitman broke into the cabin that night. They distract Sewon’s wife by letting the cat free. While she is occupied, they kidnap Sewon’s son and replace him with another child with a long stapled incision on his head. They then set the cabin on fire. Sewon has a new piece of the puzzle. The child that replaces Sewon’s son could be evidence. Sewon digs up his son’s grave.

Back in the city, Jiun and her partner visits Namil’s mother and find her with bruises and cuts. Jiun suspects the hitman is behind the door and intervenes, but he gets away. Looking for clues, Jiun’spartner learns Namil boarded a bus to Hapcheon. After looking at Namil’s prayer book and beads, she deduces he went to a temple.

Sewon learns the meaning behind the drawing and its connection to his son

Character Dr. Hyun Soo-Jung from 'Dr. Brain' Episode 4 wearing lab coat in office.
Character Dr. Hyun Soo-Jung from ‘Dr. Brain’ Episode 4 | via Apple TV+

RELATED: ‘Hellbound’ Explained: What Happened to Jung Jin-soo in Episode 3 of the K-Drama?

After Sewon gathers bone samples from the grave, he goes home and learns it is not a match for his son. He tells his comatose wife and breaks down lamenting never believing her. Using the child’s surgical scar as a clue, Sewon learns the child had a brain abnormality. He remembers his wife talking about a special clinic from episode 2 and a memory of a nurse taking his son away.

Sewon goes to the Sarea Children’s Clinic and asks to meet the head doctor. The nurse realizes who he is and looks worried and calls someone. While waiting, Sewon finds a butterfly glass ornament. It is the same image Junki’s daughter drew. Junki’s memory reveals his daughter saw a doctor taking away Sewon’s son. Sewon meets Dr. Hyun Soo-Jung (Lee El) and asks for his son’s medical records.

Soo-jung looks worried and messages someone named Mr. M and escapes the office. But one of Sewon’s memories has him realize she is the doctor who took his son. In the hallway, Soo-jung is told to take care of Sewon. Looking through her office for clues, he finds a hidden photo of Soo-jung and other doctors. The shocking twist is revealed when it shows her standing next to Namil and Dr. Myung (Moon Sung-Geun), Sewon’s mentor and foster parent.

Dr. Brain is available to stream on Apple TV+.