On what seems like an ordinary day, Johanna Shannon (Elisabeth Röhm) prepares to dispose of something wrapped in a sheet while her daughter Clare (initially portrayed by Raegan Revord) rides her bicycle with their dog, Max. As Johanna appears lost in thought, Clare’s day takes a tragic turn when she discovers her mother hanging in the attic after returning home. This distressing scene transforms into a haunting nightmare, waking teenage Clare (now played by Joey King) to face a new day.
Clare heads to school, encountering her Uncle August (Victor Sutton), who is deemed off-limits by her father. Distracted, she narrowly avoids an accident with Darcie Chapman (Josephine Langford), a popular girl, which results in an embarrassing scrape on her knee. At school, Clare grapples with her embarrassment as she observes her father, Jonathan (Ryan Phillippe), dumpster diving for oddities, a sight that leaves her mortified. Amidst her struggles and secret crush on Paul Middlebrook (Mitchell Slaggert), Clare's social woes escalate when Darcie purposely humiliates her.
Upon returning home, Clare discovers a mysterious music box that she learns has the ability to grant wishes. Initially, she scoffs at this notion. However, things take a sinister turn when after confronting Darcie, Clare impulsively wishes for her to "go rot", unwittingly unleashing dire consequences as Darcie begins to suffer severely from a bizarre affliction. The news spreads quickly through the school, leaving Clare with mounting guilt, especially after the death of her beloved dog Max.
Fuelled by her complicated feelings for Paul, Clare next wishes for him to fall madly in love with her, and unexpectedly, her wish comes true, leaving her in the spotlight. However, this newfound attention comes at a cost, as tragedy strikes with the death of Uncle August after a freak accident while he prepares for a bath. This prompts Clare to wish she would inherit August's fortune, and soon, her desires manifest into a lavish lifestyle, drawing her farther away from the reality of her actions.
Yet as Clare's popularity grows, so too does the chaos surrounding her. Following a harrowing curse associated with the music box, Clare witnesses the horrific fates of those around her, plunging her into an impossible moral crisis. Her friendship dynamics shift and she faces tangible loss, leading her to grapple with the consequences of her reckless wishes.
When tragedy culminates in a series of devastating events, including the death of a close friend, Clare realizes the music box harbors dark secrets that demand a blood price for each wish granted. Guided by her friend Ryan Hui (Ki Hong Lee), they delve deeper into the box's history, discovering that it has brought ruin to all who sought its power.
As Clare lashes out against the box and attempts to undo her previous wishes, she finds herself in a relentless battle against fate. In a desperate bid to reclaim her family, she wishes for her mother's life to be restored, only for it to lead to her father’s tragic demise instead. In a frantic conclusion, Clare wishes to turn back time to the day before the music box entered their lives.
Waking up on that fateful morning, Clare's attempt to rewrite history culminates in a tragic accident, leaving her life hanging by a thread. In the after-credits scene, the music box's legacy continues, as Ryan discovers its secrets, leaving us with a chilling reminder of the consequences of greed and desire.
