Grafted

Wei kills Angie in a moment of intense emotional upheaval after Angie destroys a shrine Wei built to honor her father and ancestors. The confrontation escalates from a verbal argument about a broken photo frame of Wei's father into violence. Wei stabs Angie through the eye in what begins as self-defense but becomes fatal when she realizes she must hide her identity to avoid detection for her crimes.

Earlier scenes establish Angie's escalating cruelty, including spreading cruel rumors about Wei and systematically undermining her dignity, building toward the explosive confrontation.

Wei uses the perfected skin-regeneration serum that she developed by combining her father's incomplete research with corpse flowers stolen from a nursery. The flowers fixed the binding flaw that had prevented the new skin from adhering properly. After killing Angie, Wei applies the serum to bind Angie's facial skin to her own body, effectively transplanting Angie's features.

Wei earlier steals corpse flowers specifically to fix the binding flaw in her father's serum, setting up the breakthrough needed for the grafting procedure.

Wei feels a deep inheritance of both her father's scientific work and his sorrow. Her father died testing the serum on himself when his skin grew uncontrollably and suffocated him. Wei becomes obsessed with completing his work partly from loyalty, partly from guilt, and partly because the research represents her only path to belonging and recognition in a world that has rejected her due to her facial birthmark.

The film opens with Wei's father testing the serum and dying, establishing Wei's personal connection to the research.

Eve unintentionally reveals to Wei (who is impersonating Angie) that she and Professor Paul have a sexual relationship. This discovery, combined with Wei's need to eliminate witnesses who might recognize her, leads her to murder Eve with a power drill. Wei then takes Eve's identity, using hair dye and colored contacts to further cement her deception.

Eve's relationship with Paul was established earlier, and her presence at the lab gives her opportunities to recognize discrepancies in the impersonation.

Jasmin visits Wei and discovers the frozen heads of Angie and Eve hidden in a refrigerator. To prevent Jasmin from exposing her identity and murders, Wei smothers her with plastic wrap. This eliminates another witness who has seen too much.

Jasmin had shown slight understanding toward Wei earlier, but the discovery of the bodies overrides any remaining sympathy.

Paul confronts Wei, revealing he has stolen her father's research notes and plans to sell them to a private firm for a fortune. Wei also wants revenge for him dismissing her from the lab and taking credit for her work. She paralyzes Paul with an injection and doses him with the flawed batch of serum that killed her father, watching as his skin consumes him from the inside.

Paul's earlier theft of the notes and his dismissal of Wei from the lab establish his betrayal as a key motivation for his murder.

Months after the murders, Wei's aunt encounters a girl who looks like Wei, and Wei is eventually revealed living on the streets as a homeless woman. However, she has physically merged with John's decaying corpse - the kind homeless man who was her only friend. This final transformation represents the complete erasure of Wei's original identity through her desperate quest for acceptance and belonging.

John was Wei's only real friend who saw beyond her appearance, and she asked him to hide her during her escape. The shattered serum sample in her pocket during the chaos foreshadows her uncontrolled transformation.

Wei switches identities multiple times to evade detection and access resources. After killing Angie, she takes Angie's face to hide the murder. When Eve becomes a threat who might recognize the impersonation, Wei kills her and assumes Eve's identity to move freely on campus and access the remaining serum samples while keeping Paul unaware of her true identity.

The escalating murders create mounting evidence that forces Wei to continuously adapt her disguise to stay ahead of discovery.

Wei steals corpse flowers because they contain properties that fix the critical binding flaw in her father's serum. The flaw prevented new skin from properly adhering to the body. The flowers become the key ingredient that finally makes the skin-regeneration serum work, allowing Wei to successfully graft Angie's face onto herself.

Paul dismisses Wei from the lab specifically because the binding flaw could not be overcome with standard methods, pushing her toward desperate measures.

Paul offers Wei a position as a research assistant because he recognizes her father's work could save his grant-driven career. However, a fundamental flaw in her father's notes prevents the new skin from binding correctly to the body. Despite Wei's efforts, Paul ultimately dismisses her from the lab when she cannot solve the problem, even though she later succeeds on her own.

Paul's interest in Wei is opportunistic from the start - he wants her father's research, not Wei herself.

Angie treats Wei cruelly as part of a social climbing dynamic, using her popularity to elevate herself at Wei's expense. Along with her friends Eve and Jasmin, Angie spreads cruel rumors about Wei and consistently undermines her dignity. This relentless bullying contributes significantly to Wei's desperation and psychological deterioration throughout the film.

The timeline establishes early that Angie's cruelty is a constant presence in Wei's life, foreshadowing the explosive confrontation to come.