In the gripping opening sequence, we witness a news report detailing the criminal background of Colin Evans (Idris Elba), who is vying for parole after serving five years for a manslaughter conviction that involved the brutal slaying of a man and five women. During his testimony before the parole board, Colin expresses remorse for his past actions, insisting that he is ready to reintegrate into society. However, the board's chairman remains unconvinced, branding Colin a malignant narcissist and violent offender, stating the families of his victims would never accept his release. The chairman's harsh words resonate ominously in Colin's mind, ultimately leading to his parole being denied.
As Colin is transported back to prison, he feigns injury with a bloody nose and requests assistance. In a shocking turn of events, he seizes a guard’s gun, puts him in a headlock, and swiftly takes control of the situation, leading to a fatal escape when he shoots both the guard and the driver.
Meanwhile, we meet Terri Granger (Taraji P. Henson), as she juggles life at home with her baby Sam while trying to manage a phone call amidst the chaos of landscapers outside and her daughter Ryan (Mirage Moonschein) playing nearby. Terri's best friend Meg (Leslie Bibb) arrives, noticing Terri's overwhelming stress, and suggests a girls' night. Later, Terri's husband Jeffrey (Henry Simmons) returns home, exuding impatience as he prepares for a trip, despite professing his love for her.
Colin, now in Atlanta, drives a van, stalking a woman named Alexis (Kate Del Castillo). He brazenly breaks into her home and confronts her about an alleged betrayal. The tension escalates to a horrific climax as Colin brutally murders her, echoing the critical voices of his past.
That evening, a storm begins to brew as Terri prepares dinner for her children. After crashing his van, Colin finds his way to Terri's home under the pretense of needing help. Graciously, Terri invites him in, unaware of his true intentions. As Colin interacts with her and her daughter Ryan, he presents himself as charming and polite, discussing his past heartbreak. However, the atmosphere shifts when Meg arrives, and Colin, suddenly malevolent, murders her with a shovel, concealing her body while Terri remains unsuspecting.
As Terri becomes aware of Meg's absence, she grows increasingly alarmed at the unsettling signs in her home—cut phone lines and missing knives. The tension mounts when Colin is discovered with Ryan, leading to a desperate confrontation where Terri fights back with a fire extinguisher, trying to protect her children.
Colin forces Terri to drive him away while a terrifying sequence unfolds wherein she attempts to alert a police officer of her perilous situation. Tragically, Colin's ruthlessness is showcased as he kills the officer, further entrenching Terri in a nightmare.
Forced to return to Alexis's home, the depth of Colin's revenge becomes clear as he takes delight in tormenting Terri, tying her up. But with quick thinking, Terri manages to escape her bindings, revealing a shocking revelation of revenge that deepens the tension. As Colin discovers her intent to protect her children, a fierce struggle ensues, advocating for both survival and justice.
In a climactic battle, Terri bravely fights Colin, injuring him before seizing his gun and firing multiple shots until he crashes through the window. As the weight of horror lifts, the police arrive alongside Jeffrey, but the confrontation leaves Terri feeling betrayed.
Time passes, and Terri moves to a new home with her children, carrying the weight of her past but beginning to forge new connections while cherishing memories of her fallen friend Meg. The new chapter is marked by sunny afternoons at the park, symbolizing hope and resilience in the aftermath of darkness.
