Character Relationship Map: Door Lock

Characters

• Jo Kyeong-min (played by Gong Hyo-jin) — protagonist

  Jo is a bank employee living alone in a small studio apartment, under financial and work-related stress. After suspecting someone is entering her home, she reports the intrusions and tries to protect...

• Oh Hyo-joo (played by Kim Ye-won) — supporting

  Oh is Jo's friend and coworker, and she supports Jo as the suspected intrusions make her afraid. She offers Jo a place to stay and is later attacked while trying to help her. In the hospital, she tell...

• Detective Lee (played by Kim Seung-o) — supporting

  Detective Lee questions Jo after Kim Sung-ho is murdered and raises the possibility that she arranged the killing and staged herself as a victim. Jo denies this, saying she was being stalked and used...

• Han Dong-hoon (played by Lee Ga-sub) — supporting

  Han Dong-hoon is Jo's former building janitor. After the investigation appears to identify a murderer, he gives Jo a penguin-shaped surveillance camera to help her feel safer and claims the killer has...

• Kim Sung-ho (played by Lee Chun-hee) — supporting

  Kim Sung-ho is a bank manager whose murder becomes central to the investigation involving Jo. Forensic investigators find evidence that he fought with a third person in Jo's studio and detect traces o...

• Kim Gi-jeong (played by Jo Bok-rae) — supporting

  Kim Gi-jeong is an angry customer who followed Jo after seeing her leave with Kim Sung-ho. He admits following them but denies killing anyone. A surveillance video appears to connect him to the crimes...

Canonical Relationships

Family, romantic, and professional connections based on plot evidence.

• Jo Kyeong-min → Detective Lee (Power Suspect And Investigator) — Lee's authority places Jo under suspicion instead of treating her only as a victim.

  Detective Lee questions Jo and suggests that she may have arranged Kim Sung-ho's murder and staged herself as a victim.

• Jo Kyeong-min → Kim Sung-ho (Professional Employee And Manager) — Their workplace connection links Jo to the murder investigation.

  Jo works at a bank, and Kim Sung-ho is identified as a bank manager. Jo is seen leaving with him before Kim Sung-ho's murder becomes part of the inves...

Story Dynamics

Alliances, conflicts, and narrative interactions that evolve throughout the story.

• Jo Kyeong-min → Han Dong-hoon (Unknown Uneasy Helper) — Han appears helpful while remaining a source of unease.

  Han Dong-hoon, the former building janitor, gives Jo a penguin-shaped surveillance camera to make her feel safer, but his familiarity with her former...

• Kim Gi-jeong → Kim Sung-ho (Conflict Potential Adversaries) — Their connection is mediated by Gi-jeong's pursuit of Jo and the murder case.

  Kim Gi-jeong followed Jo after seeing her leave with Kim Sung-ho, and the investigation examines whether Gi-jeong is connected to the crimes surroundi...

• Kim Gi-jeong → Detective Lee (Conflict Suspect And Investigator) — Gi-jeong becomes the police's principal suspect.

  Police believe surveillance footage showing a toolbox, hammer, and saw with Gi-jeong's fingerprints gives them enough evidence to arrest him.

• Kim Sung-ho → Detective Lee (Narrative Murder Investigation) — Sung-ho's death gives Lee the central case to investigate.

  Kim Sung-ho is found murdered, and Detective Lee questions Jo while investigators examine the evidence connected to his death.

• Jo Kyeong-min → Kim Gi-jeong (Conflict Stalker And Target) — Gi-jeong's unwanted pursuit intensifies Jo's fear and suspicion.

  Kim Gi-jeong becomes angry after Jo refuses his attempt to turn a sales conversation into a date, and he later follows her after seeing her leave with...

• Jo Kyeong-min → Oh Hyo-joo (Alliance Supportive Coworkers) — Hyo-joo is Jo's main source of practical and emotional support.

  Oh Hyo-joo is Jo's friend and coworker. She supports Jo's fears and offers Jo a place to stay.

Story Analysis

A woman facing stalking, institutional suspicion, and unreliable protection struggles to determine whether the danger has truly ended.

Plot Progression

1. A Life Without Security — Jo struggles with unstable employment and financial pressure while living alone. After an aggressive customer reacts badly to her rejection, she begins to fear that her apartment is being entered.
2. The Apartment Becomes Evidence — Jo reports suspicious sounds, but the building's corridor cameras are fake and provide no protection. Hyo-joo offers support just as Kim Sung-ho is found murdered and Jo discovers signs of an intrusio...
3. Victim Under Suspicion — Jo survives an attack by a man who appears to know her, yet the police begin treating her as a possible participant in the murder. Forensic findings and Detective Lee's questions intensify the pressur...
4. A Convenient Suspect — The investigation shifts toward Kim Gi-jeong because he followed Jo and is connected by surveillance evidence to a toolbox, hammer, and saw. Police believe the evidence is sufficient for an arrest, bu...
5. Safety That Does Not Hold — Hyo-joo is attacked while trying to help Jo, and Jo visits her in the hospital. Han gives Jo a surveillance camera, but the final call from Detective Lee leaves Jo's safety and the identity of the dan...