A man finds himself in a dire situation, running away from an unknown threat. He seeks refuge in a locker room, where facing the many reflections of himself becomes a terrifying ordeal. As he approaches the largest mirror, it suddenly starts to crack, prompting him to frantically apologize to his reflection. In a desperate bid for redemption, he tries to fix the damaged mirror but inadvertently meets a grim fate as his own reflection slits his throat, despite him not physically doing so.
Fast forward to some time later, we meet Ben Carson (Kiefer Sutherland), a former undercover detective who has been marginalized after an officer-involved shooting. Struggling with his demons, he is compelled to accept a night security position at the Mayflower, a department store built on the ashes of a psychiatric hospital infamous for its dark past of treating patients with schizophrenia. This location is notorious for a horrifying mass killing in 1952, which led to its closure.
As he begins his shifts, Ben can't shake off a sense of unease; he notes the impeccably clean mirrors that had obsessed the previous guard. On his first night, he witnesses a door open in a mirror's reflection, prompting an investigation that yields no answers. The following nights plunge Ben deeper into terrifying visions that he initially dismisses as the side effects of medication prescribed to curb his alcohol addiction. His nights become haunted with strange handprints appearing on the mirrors, leading him to touch one, resulting in injury from broken glass.
Ben's psychological turmoil escalates as he feels engulfed by visions of a fire and hears whispers of past victims who perished horrifically in the store. Amongst the chaos, he finds a wallet belonging to Gary Lewis, the previous watchman, with cryptic clues pointing to a name—"Esseker." He receives a chilling package from Gary, filled with newspaper clips about the devastating fire, only to learn that the man responsible for the Mayflower’s destruction also ventured into unspeakable crimes, including family murder.
Ben confides in his younger sister, Angela (Amy Smart), about his haunting experiences, though she remains skeptical. This disbelief ironically juxtaposes their next encounter when Ben decides to visit Gary's body at the morgue, where he uncovers a startling detail—the bloody glass shard depicted in Gary's death photo differs from reality, confirming the mirrors’ sinister influence.
Meanwhile, Angela's ill-fated bath time turns monstrous when her reflection ensnares her, gruesomely tearing her jaw, leading to her death. Devastated, Ben returns to confront the mirrors but finds them mysteriously persistent against his attempts to destroy them. Faced with cryptic messages, he digs deeper into the store's past and discovers the name Anna Esseker, a psychiatric patient supposedly dead during the infamous mass killing, yet she had been transferred just days before—adding yet another layer of horror.
Realizing the mirrors threaten his family, Ben latches onto the idea that he must bring Anna back to safeguard them. As he tries to warn his estranged wife, Amy (Paula Patton), she dismisses his dire warnings, certain he’s losing his grip on reality. However, events take a dark turn when their son Michael begins conversing with his reflection, pushing Amy to fearfully reach out to Ben, who quickly joins them to cover every possible reflective surface in their home.
Ben's search for Anna leads him to discover her troubled past, revealing that her torment stemmed from demonic possession—thanks to the psychiatric practices of her time. Despite her refusal to return with him initially, Ben’s home is still besieged by the evil lurking in the mirrors. In a twist of fate, Michael unwittingly unleashes the danger by cleaning away protective paint, which culminates in a desperate confrontation with the reflection that nearly takes him.
After a frantic series of events involving Anna’s possession and a final showdown with the horrifying demon, the building crumbles around them, seemingly claiming Ben as well. Yet, amid the chaos, Amy desperately rescues Michael from drowning, showcasing the unyielding bond of a mother’s love.
As Ben emerges from the rubble, he becomes disoriented by the oddities surrounding him, including the reversed inscriptions on badges and vehicles, leading him to a harrowing realization of his demise—he is trapped in a mirror world. The film concludes on a haunting note, with Ben’s handprint manifesting on the surface of a mirror, symbolizing his eternal entrapment as the screen fades to black.
