By the glow of the moonlight, three lifeless bodies rise to the surface of the Connecticut River in western Massachusetts. At South Station in Boston, [Thomas Craven](mel-gibson) receives his daughter, Emma (Bojana Novakovic), who has come back for a visit. Unfortunately, during the ride home, she experiences nausea and throws up. As Thomas prepares a meal, Emma suddenly starts to bleed from her nose and vomits violently. In a rush to get her to a hospital, tragedy strikes when a masked gunman yells "Craven" and fires two shots, fatally wounding Emma, who dies in her father's arms.
Initially, it seems that Thomas, a police detective, was the intended target. However, as he investigates further, he discovers a gun belonging to Emma's boyfriend, David (Shawn Roberts), leading him to suspect that she may have been the actual target. David is anxious about the company known as Northmoor, where Emma worked, and Thomas learns that she had uncovered their plans to manufacture nuclear weapons, which were designed to be traced back to foreign nations if used as dirty bombs. After an activist group's break-in fails, Emma becomes poisoned with thallium, hidden in a carton of organic milk.
While burning Emma's belongings in his yard, Thomas runs into [Jedburgh](ray-winstone), a "consultant" sent to either prevent him from uncovering Emma's secrets or eliminate him. However, the two men form an unexpected bond, allowing Thomas to continue his investigation. Throughout his journey, Thomas experiences haunting visions of his daughter, engaging in brief conversations with her spirit.
As he delves deeper, Thomas confronts Northmoor mercenaries and uncovers the truth about Emma's murder, linking it to [Jack Bennett](danny-huston), the head of Northmoor. He learns that Bennett ordered the killings of his daughter and her activist allies who were aiming to gather evidence against the illegal operations. Meanwhile, Northmoor operatives set up David to take the fall for Emma's murder, and they attempt to silence another activist who had shared information with Thomas.
Confronting a lawyer and a Senator whom Emma had contacted reveals that they are aware of the conspiracy, but their intentions are murky. Bennett has the intention of poisoning Thomas with thallium just as Emma was poisoned, leading to a harrowing confrontation at Bennett's home. Despite being shot, Thomas manages to overpower Bennett and force-feed him the contaminated milk, rendering deadly justice for his daughter's murder.
In the aftermath, Thomas finds himself fighting for his life in a hospital bed due to the poisoning and gunshot wounds. Meanwhile, Jedburgh meets a different fate as he dispatches the Senator and his cohorts—his own web of betrayal unraveling—as he contemplates the morality of his actions amidst his terminal illness. Just as the Senator's assassination is about to be spun in the media, Jedburgh's own life is snuffed out by a young State Trooper.
As Thomas lays dying, he enters a spectral moment where he sees Emma approach him in the hospital room. She leans down to whisper comfort in his ear. Shortly thereafter, a young reporter receives a package from Thomas containing crucial DVDs that expose the conspiracy, ensuring the downfall of Northmoor. As Thomas breathes his last, he and Emma walk away together, leaving the stark realities of life behind and stepping into a bright, welcoming light.
