After moving into a new apartment to escape her troubled past and an abusive ex-husband, Mary Kee begins to experience strange and unsettling events. She becomes fascinated with an old rotary phone she finds, feeling an immediate attraction to its vintage charm. She places it prominently in her home, unaware that this decision will set off a series of eerie and supernatural occurrences.
Soon after setting up the phone, Mary starts receiving mysterious calls from a woman named Rose. Over time, she learns that Rose claims to be calling from the past, specifically from the year 1979. An unlikely friendship develops between the two women, with Rose sharing details about her own life, including her abusive marriage and tragic death by suicide. As their conversations deepen, Rose reveals her own dark secrets and her connection to the apartment.
The situation takes a horrifying turn when Rose, driven by her own revenge, begins to kill others connected to Mary's life, including her abusive ex-husband. Rose's actions escalate as she murders the man, bricking up his body in the pantry where Mary eventually discovers it. Mary also learns from the handyman George, who has been in the apartment since 1979, that Rose had a similar abusive relationship and that she herself killed in her attempt to escape her torment. Rose's influence extends beyond that, as she kills George in the past and later targets Mary's current boyfriend, John, a teacher with a background in science and time. Tragically, Rose also kills John as a child and buries him in the same pantry, a fact no one else remembers except Mary.
As Rose's phone calls become more disturbing and threatening, Mary feels increasingly haunted and frightened within her own home. She cuts off contact with Rose but soon regrets it, as Rose becomes enraged and begins to hunt her through time. Rose's wrath culminates in her warning Mary that she plans to take revenge not just on the present-day Mary but on her as a child in the past. Rose finally lures young Mary into the apartment, attempting to burn her with hot water, leaving visible scars on adult Mary.
Realizing she must stop Rose before she destroys everything, Mary discovers that Rose had been institutionalized but has mysteriously disappeared after her release. As Rose's threat grows more personal and deadly, adult Mary learns she must take drastic action. With her knowledge of the past and the future, she enlists her childhood self to defend her. In a desperate and heartbreaking act, little Mary stabs Rose with a shard of glass from a mirror, ending her reign of terror. After Rose's demise, Mary hears her younger self sobbing over the loss, and she advises her to escape from the apartment immediately.
However, in a disturbing twist, the timeline seems altered. Mary finds herself back in the same apartment with her ex-husband, who becomes hostile. In a final act of desperation and justice, Mary kills her ex-husband and bricked-up body in the pantry, seemingly fixing the chaos but leaving lingering questions about her fate. In the deleted ending, a young couple moves into the apartment, and the now-quiet rotary phone begins to ring once again, hinting that the cycle may not be truly over.
Throughout the film, themes of trauma, revenge, and the supernatural blend into a haunting story about confronting one's past and the dangerous power of unresolved anger. The supernatural elements, combined with the psychological horror, create an intense atmosphere that keeps viewers questioning what is real and what is supernatural, culminating in a chilling conclusion that leaves lingering doubts about whether the cycle of violence can ever truly be broken.
