The film opens with a stark, unsettling scene inside an apartment: an elderly woman enters to find another older woman lying dead on the floor, a half-eaten birthday cake left on a table, and a young, blond naked woman greeting her with a kiss. The mood immediately hints at something uncanny lurking beneath ordinary life.
Back in Paris, Susana, a fashion model, calls her grandmother Pilar and tells her she won’t be in Madrid for her birthday. Not long after, a hospital in Madrid rings to deliver shocking news: Pilar has suffered a brain hemorrhage. As Pilar’s only living relative, Susana travels to Madrid to bring her grandmother back to her apartment on Calle de Alfonso XII, near El Retiro, where Pilar is revealed to be the same elderly woman from the opening. From the moment she arrives, Susana feels a strange undercurrent in the place, and the days begin to blur as disturbing dreams haunt her nights.
As Susana settles in, she encounters Eva, a visiting young woman who claims to be the niece of Pilar’s best friend Julita. Eva, who seems both familiar and elusive, explains that she and Susana have met before, though Susana cannot remember. Eva’s visit unsettles Susana further, and a long-buried memory begins to surface when she p picks up her childhood diary and revisits a birthday party where Eva and Julita stood by as a strange ritual unfolded. During that party, the two girls had locks of hair cut, and from that moment on, Susana finds herself plagued by increasingly vivid nightmares tied to Pilar. Susana also starts suspecting that Pilar might be moving through the apartment at night, a thought that fills the rooms with an eerie, almost living presence.
As the days pass, Susana’s attempts to reclaim her independence become fraught with danger. She tries to move Pilar toward a nursing home, but Pilar’s supernatural nature makes the plan fail in alarming ways. In a cruel turn, Pilar causes the death of Adela, a domestic worker Susana had hired to help care for Pilar. Later, a fire erupts at the nursing home, killing all the guests, while Pilar is seen back in the Madrid apartment, seemingly unharmed and unfazed by the chaos. Susana’s resolve hardens: she decides to end Pilar’s hold on her.
The final, shocking act unfolds when Susana poisons Pilar’s soup, killing her grandmother. Moments after Pilar’s death, the phone rings again—Eva’s voice crackles through the line, the call revealing that Eva recognizes Susana’s true identity as Pilar’s voice from the past. In a tense echo of the opening, Eva asks, “Are you sure?” and the atmosphere thickens with inevitability.
Pilar—still powerful and elusive—uses her occult abilities to disrupt the space, moving objects and trapping Susana in the apartment. Susana flees into the bathroom and discovers a painting of Pilar in her youth, which now appears to show Susana. In a final, supernatural twist, Pilar transfers her soul into Susana’s body, leaving the living Susana’s selfhood to fade into the background. The painting’s image shifts to reflect the new presence, signaling a complete swap of identities.
Eva reappears, revealed as the young woman from the very beginning, and the two women share a charged, intimate moment as the film closes, leaving the audience with a haunting sense of transformation, desire, and unresolved history that lingers long after the credits roll.
