Detective Malcolm “Mal” Toohey, Joel Edgerton, is shot during a raid on a drug lab and saved by his protective vest. After celebrating, he drives home drunk and strikes a young boy on a bike with his side-view mirror. He calls an ambulance but denies any involvement in the accident. When honest young detective constable Jim Melic, Jai Courtney, and his cynical older partner Carl Summer, Tom Wilkinson, arrive on the scene, Carl recognizes Mal and sends Jim to secure the perimeter. He questions Mal privately and sends him home, leaving Jim increasingly suspicious.
The boy is identified as William Sarduka, and Jim soon falls in love with William’s mother, Ankhila. Meanwhile, Carl becomes fixated on proving that a pedophile named Victor is responsible for the abduction and rape of a young girl. During a court hearing, Victor is released on bail. Carl uses the moment to criticize and challenge the legal system, prompting intense debate about justice and consequence. At a secret meeting with Carl, Mal expresses a desire to come clean and take responsibility for the accident, but Carl urges him to keep quiet for their own sake, and Mal cannot commit to a path forward.
Mal and his family visit Ankhila and William in the hospital. Back at home, Mal confesses to his wife, Julie, that he hit William, and learns that the boy has brain damage and may not survive. The revelation drives a wedge between Mal and Julie, and their relationship grows distant under the strain. Carl finds Jim in the hospital parking lot but cannot persuade him to back off, and his determination only seems to strengthen Jim’s resolve to investigate Mal. Jim offers to accompany Ankhila to the hospital, and she accepts. At her apartment, he attempts to kiss her, but she rejects him. They travel to the hospital in silence, only to learn that William has died. Jim stands alone in the corridor outside the room, crushed and alone.
Mal arranges a final confrontation with Carl and Jim, telling Jim that he intends to come clean about the accident. Carl mocks Mal for his weakness, then turns his taunt toward Jim, accusing him of sleeping with Ankhila and suggesting he might be struck by AIDS. In a sudden struggle, Jim overwhelms Carl with a headlock until Mal intervenes and Carl collapses, unconscious. Jim calls for an ambulance as Mal tends to him.
Mal later visits Carl in the hospital, where the other man appears to have suffered a stroke and can only utter a few phrases—“yeah” and “good.” In the corridor, Mal informs Jim that doctors warned Carl’s condition would deteriorate soon, offering a grim sense of inevitability. He also reveals that there are no cameras in the back of Tamberine’s—the building where the trio had met—hinting that Mal now knows Jim’s secret, just as Jim understands Mal’s moral conflict. Driving past William’s school, Mal sees children calling his victim’s name and then crashes into the back of a passing truck, bleeding heavily from a head wound. Slumped, he staggers to a nearby bench, then collapses outside Ankhila’s residence and drifts into unconsciousness.
When paramedics arrive, the police question Ankhila, and Mal, waking, insists that she did nothing to him. He repeats that sentence for a moment, then finally confesses, “I did it,” with tears in his eyes, and apologizes. Ankhila seems to realize that Mal was responsible for William’s death but tells the police only that Mal had helped her son. The film ends with Mal and Julie taking their children to school. Across the street, they see Jim leaning against his car with two cups of coffee, suggesting that Mal is about to become Jim’s new partner.
