As Thana makes her way home after another exhausting day in the bustling atmosphere of New York City's Garment District, her life takes a harrowing turn following a series of violent events that shatter her world. In a dimly lit alley, she finds herself under the threat of a vicious assault from an unknown attacker, leaving her feeling utterly broken and vulnerable. The trauma only intensifies when she returns to her sanctuary, only to confront a second assailant, who meets a gruesome fate at the hands of Thana's determination, wielding a small glass apple and a trusty iron to defend herself.
The following day, as she struggles to piece together the fragments of her psyche, her coworkers grow increasingly concerned about her disquieting demeanor. The meticulous attention to detail she once possessed begins to wane, replaced instead by a looming sense of detachment. Meanwhile, in the hidden shadows of her apartment, Thana engages in a morbidly meticulous ritual, dismembering her second attacker's lifeless body and carefully storing the grisly remains in her refrigerator.
As the darkness within her seeps into her daily life, her once immaculate bathtub becomes a grim testament to the chaos she has unleashed. Each shower transforms into a haunting scene where the specters of her past visit her in the form of distressing hallucinations. The unsettling sounds of bodily fluids swirling down the drain further fracture her tenuous grasp on reality.
Mrs. Nasone, her observant neighbor and landlady, starts to sense the profound turmoil haunting her tenant, yet remains blissfully unaware of the horrific acts committed within those very walls. As Thana navigates the unpredictable streets of the city, she finds herself shadowed by a leering young man, who unwittingly mistakes one of the bagged body parts for litter, leading him to a violent end at the end of her gun.
In the wake of this chilling encounter, Mrs. Nasone's instinct urges her to seek medical assistance for Thana, who continues to spiral into isolation, her grip on sanity slipping further with each moment as she attempts to rationalize the chaos around her. Meanwhile, Phil, Mrs. Nasone's loyal dog, develops an unsettling curiosity for the contents of the refrigerator, hinting at the macabre secrets concealed inside.
As the grim discoveries begin to capture the attention of the media, Albert invites Thana into his office, his gaze lingering significantly on her neck as he mentions an upcoming Halloween party at work, promising that "there will be many boys there [her] age." Thana's reply is a cryptic promise: "I'll try." Her quest for vengeance escalates as she starts targeting men who have wronged her, including a smug fashion photographer, a vicious pimp, gang members who attempted to assault her, and even a Saudi Arabian businessman and his limousine driver, deriving a grim satisfaction from her actions.
With Thana's work performance deteriorating, Albert begins to notice her evasive behavior after dinners with colleagues. To conceal her absence from scrutiny, she agrees to accompany him to the party. Unbeknownst to them, Phil has grown particularly interested in the scent of the dismembered body parts, leading Thana to take him for a walk, subsequently tying him to a park post, leaving a note suggesting he simply wandered off but would soon return.
At the Halloween bash, Thana dresses in a nun's habit alongside Albert, while Mrs. Nasone investigates her apartment, stumbling upon the grisly remnants of the burglar's decapitated head. Mistakenly believing that Thana has committed the atrocities and harmed her dog, Mrs. Nasone promptly alerts the authorities, reporting her tenant’s whereabouts. During the party, Albert attempts to seduce Thana upstairs, only to be met with a barrage of gunfire as she retaliates, resulting in chaos among the partygoers, while her coworkers racing to help soon realize Thana is behind the mayhem.
In a shocking turn, just when hope seems lost, Laurie seizes a nearby knife and plunges it deep into Thana's back. As she spins around, her gun still aimed at Laurie, Thana's anguish and desperation transform into a primal scream: "Sister!" before she collapses, her lifeblood seeping into the floor. In the aftermath of this party massacre, Mrs. Nasone finds herself attending a memorial service for her husband and Phil, remaining blissfully ignorant of the fact that her cherished dog has somehow survived and is clawing its way back through the debris of their apartment door.
