NOTE: Another great spoiler sent in by Marcus.

The film begins with home videos of the Hume family – Nick (Kevin Bacon), Helen (Kelly Preston), Brendan (Stuart Lafferty), and their youngest son Lucas (Jordan Garrett). Nick gives Brendan a hockey stick for Christmas, and it shows him teaching him how to hit a puck (along with his hockey skills progressively getting better, including being awarded MVP for his team). Lucas is more like his mother, and likes to paint. Nick works as a risk assessment executive for a big firm. He briefly talks with his co-worker Owen (Rich Ceraulo) about an account, which had a statistic that married men with two kids are more likely to live longer. Nick goes home to see his two sons squabbling while eating dinner. Lucas is fed up with Brendan’s cocky attitude, and Brendan tells him that he’s just jealous. Tomorrow night is Brendan’s next hockey game, and so Nick is going to drive him, since it’s in the city. He asks if Helen is going to come, but Lucas has something else going on that night, and so she’s going to be with him. Brendan and Lucas rough around after eating dinner, and then later on we see Nick cheering for Brendan at the hockey game. On the way home, Brendan says that some of his friends are thinking about going to college in Canada. Naturally, he wants to go with them so that he can pursue playing hockey professionally. Nick thinks that it’s too far away, but eventually says that he’s okay with it. Two cars speed down the road without their headlights on. Nick flashes his lights to remind them, but they speed past him. As Nick and Brendan continue to talk, the two cars come back and speed up ahead of them. They startle Nick for a while, but end up turning off the street. Nick doesn’t know where the freeway ramp is, and finds that he’s running low on gas.

They stop at a gas station, where Nick starts to fill his car. Brendan gets out and tells him that he’s going inside the store, since he needs a drink. Nick tells him to hurry up, and then calls Helen. He jokes that their son is going to run away to Canada for college and they’ll never see him again. The two speeding cars pull up to the gas station, and all the men inside get out wearing masks. They burst into the store and tell the clerk and Brendan to keep their hands up. The clerk makes a move for his gun, and has his chest blown apart by a shotgun. The leader of the masked guys urges one of his buddies to kill Brendan. Nick tries to run to the store, but is hit by a scared driver. Brendan has his throat slit open with a machete. The masked guys run back into their cars, except for Brendan’s killer, who’s still shook up about what he just did. The gang speeds off, but before the killer can run away Nick tackles him. He removes his mask and sees his face, but he knees Nick in the side and runs into the middle of the street. He’s pissed that his friends left him, and then is hit by a car from behind. While driving away, Billy Darley (Garrett Hedlund), the leader of the gang, takes off his mask and laughs with his boys. Bodie (Edi Gathegi) asks if they should go back for Joe (Matt O’Leary). Billy says that he’s a man now and can take the subway, not knowing that he’s been caught. Nick rushes to Brendan, who’s painfully dying from his wound. They are taken to the hospital, where Nick is forced to wait outside while the doctors do what they can. Helen and Lucas arrive at the hospital just in time to hear that Brendan is dead.

Nick goes to the police station, where Detective Wallis (Aisha Tyler) has six guys in a line-up, and asks him to identify his son’s killer. Nick positively identifies Joe as being the killer, and remarks about how young he is. Wallis tells him that even though he’s young, he’s still an animal. The Humes have a funeral for Brendan, and afterwards Nick says that tomorrow he has to go to court for a pre-trial hearing. He asks if Helen wants to come, but she tells him to go alone. While lying in bed, Helen says that the hockey team wants to have a memorial for Brendan at the next hockey game. Helen ends up weeping uncontrollably, and Nick embraces her. Lucas has a hard time going to sleep, and so he walks into Brendan’s room. He breaks down and cries when he looks at a photo taken with his brother. The next day, Nick goes to the court, where the attorney is confident that they can win this case, and guarantees that Joe Darley will be sentenced to 3-5 years. Nick wants him to be put away for the rest of his life, but the attorney explains that they could lose the case if they push for a life sentence. The gas station didn’t have a camera, the machete disappeared, the only blood found on Joe was his (from getting hit by the car), and the only witness is Nick. It is also revealed by Wallis that Brendan’s murder was an initiation kill for the gang. In order to become part of a gang, they have to kill an innocent. Nick can’t believe that his son was murdered for such a stupid reason, and is ultimately given the choice about testifying or not.

At the hearing, Nick looks over at Joe, who stares back and makes a threatening gesture towards him. Nick tells the judge that he is not going to testify, claiming that it was dark and he could no longer identify Joe as the killer. Wallis is surprised by this, and the judge releases Joe on bail. Nick exits the courtroom first and waits in his car outside. The gang drives up to the courthouse and celebrate Joe being freed. Billy tells Joe that he’s a man now, and tells him to get in the car. The gang takes off in their two cars, and Nick follows them to their neighborhood. He sees Billy drop Joe off at his apartment building, and gives him a wad of cash. Nick drives back to his house and looks for weapons in his tool shed. He picks up a machete, but gets emotional thinking about Brendan. He finally decides on a rusty blade, and then Lucas walks in. Nick keeps the blade out of sight, and gets after Lucas for picking up the machete. Lucas asks where Brendan was killed, and Nick tells him where the gas station is. Helen also walks in and asks what’s going on. Nick tells them that he forgot something at the office, and he’ll be back later. He drives back to Joe’s apartment building, and sits in his car. He thinks he’s crazy for doing this, and so he starts up his car to leave when he sees Joe walking outside to throw away his garbage. Nick changes his mind and decides to go through with it. Joe smokes a cigarette and walks off with his garbage bags. Nick gets out of his car and walks towards the building, but stops when a girl walks out and notices him acting strange. The girl leaves, and so Nick goes to the garbage bin where Joe is. Joe is startled, and then remembers who Nick is. Nick grabs onto him and hits him repeatedly. The two fight each other, ending up around the corner. During the struggle, Nick loses the knife and Joe grabs it. He slices Nick’s hand, and Nick takes the knife back and stabs Joe in the chest. He dies, and Nick is shocked at what he just did. He pulls the knife out of Joe’s chest and drives off. After wiping his fingerprints off the blade, he tosses it into a river.

Nick goes back home, where Helen and Lucas are arranging video tapes while watching home videos of Brendan. Helen grows concerned once she sees Nick, but he tells her that he slipped and cut his hand. She goes to get bandages, and Nick asks Lucas how he’s doing. He says he’s doing alright, and then Nick tells him that he’s going to take a shower. In the shower, Nick breaks down and cries, while Helen comforts him. The next day at work, Owen comes into Nick’s office and talks with him. He tells him that the company will pay for him to attend therapy if he wants, but he declines. Wallis shows up and tells Nick that Joe Darley was found dead. Nick tries to act normal and says that it was probably another gang killing. Wallis gets suspicious when she sees Nick’s bandaged hand, and ends up leaving. Elsewhere, Billy goes to a chop-shop owned by his father, Bones (John Goodman). Billy pays him some money back that he owes him, and Bones make it clear that he hates him. Billy then goes to his gang’s resting place, where everyone is quiet. He asks them what’s going on, and Bodie informs him that Joe was murdered. Furious, Billy leaves. Later on, the gang meets at their bar and toast to Joe’s memory. Billy walks in and gets pissed at them for drinking instead of doing something constructive. He cools down though and tells them that they’re going after Joe’s killer. They all deduce that it wasn’t a rival gang, and then one of the goons says that his sister saw someone in a suit lurking around the apartment building when she left that night. Billy figures that it was Nick, and finds that his picture is in the paper for his son’s death. The goon shows the paper to his sister and she confirms that Nick was the lurking man.

Nick tries to live his life normally, and leaves from work in the afternoon. While walking down the street, the gang stalks him. Bodie walks behind him and prepares to shoot him, but Nick knocks the gun away with his briefcase and beats Bodie. The others come out from hiding and chase after Nick. Billy fires at him in the middle of the street, and the gang chases him through alleys. Nick, panicked and scared, runs for his life and is narrowly shot by Billy. He loses his briefcase and runs through a kitchen, locking the door. He finds an exit and continues to run. The gang knocks their way into the kitchen, and Billy forces a chef to tell them which way he went. Nick eventually winds up at a parking garage, and accidentally causes a car’s alarm to go off. He runs up through the levels of the garage, jumping on other cars so that their alarms will go off and distract the gang, which works. Nick is exhausted by the time he gets to the roof, where his car is parked. A goon runs to the roof as well and searches for him with his pistol. Nick distracts him by unlocking his car, and then tackles him to the pavement. He smashes his head onto the ground and beats him up. Nick tries to enter his car, but the goon grabs him from behind, so he smashes his body through the car window behind him. Nick unlocks the door and smashes the goon’s head with the car door. He tries to shoot Nick, but misses. They continue to fight inside the car, and it starts to roll back towards the edge of the roof. Nick is choked, but gets the upper hand and ties the seatbelt around the guy’s throat. Nick jumps out of the car just before it falls off the roof, killing the henchman. Nick gets into his car and drives away. Billy and his boys are forced to leave as well when they hear police sirens in the distance.

Nick speeds through the streets and gets a call from his wife. She’s upset that Lucas is nowhere to be found, but Nick has an idea of where he is. He hangs up and speeds off to the gas station, where sure enough Lucas is. He tries to get him in the car, but Lucas refuses to leave. He finally breaks down and tells him that he should’ve been the one to die, since the family could go on without Lucas better than they could without Brendan. Nick gets him inside the car and drives him home. Later on, Detective Wallis is called to the crime scene to investigate what happened. Unfortunately, Billy was able to retrieve Nick’s briefcase, which contained his wallet. The next day at work, Bodie is sent to Nick’s office building with a package. A security guard tries to get him to sign in for the package, but Bodie ignores him and goes up in the elevator. He walks through the office, yelling for Nick and pushing co-workers around. When he finally finds him, he gives him the package and tells him that he won’t have to worry about dying alone. Security guards escort Bodie out of the building. Nick opens the package and sees that it’s his briefcase. He looks through his wallet and finds that his family picture has all the faces marked with red. On the back of the picture is a phone number, and so he calls. Billy answers the phone at the bar, and taunts Nick. Nick tells him that he’ll gut him like he did with his friend, and Billy tells him that Joe was his brother. Billy puts a death sentence on Nick’s family and hangs up. Nick panics and calls Wallis. He tells her that the gang has threatened to kill his family, and pleads with her to send over cops to protect his wife and son. Nick leaves from work and tells Helen to stay at home with Lucas. He drives home and locks all the doors/windows. Wallis shows up and tells him that she’s going to leave a cop car outside for the night. She has a pretty good idea that Nick killed Joe and brought this upon himself. Nick however won’t admit to it, and so she tells him that if he started a war, may god help him. Helen gets upset with Nick, since she knew that something was wrong with him over the last couple of days. Nick runs outside and tells Wallis that he doesn’t care what happens to him, just as long as his family is safe. She tells him that the cops are on the lookout for Billy and his gang, and leaves.

That night, Nick stays awake while Helen and Lucas sleep. Two cops wait outside in their car. Suddenly, Nick hears a car horn. He goes to the front window and sees that the two cops have had their throats sliced open; the horn is from the dead driver’s head resting on it. Before he can react, Nick is attacked by the gang, who are already inside the house. He beats one of them with a baseball bat, but retreats upstairs while a goon tries to shoot him with a shotgun. They wind up in the bathroom, where Nick pulls the rug out from underneath him, causing him to land hard on his back. Another goon tries to shoot Nick, but he shuts the door on the shotgun, which causes him to shoot the other guy in the leg. Nick then tackles the henchman down the staircase, landing hard on the floor. Billy and his boys grab Helen and Lucas, bringing them downstairs. Billy looks Nick dead in the eye, and then shoots Lucas in the head. Nick gets up and runs towards him screaming. Billy shoots Helen through the chest, and then shoots Nick in the chest. Satisfied, the gang leaves while the Hume family are all left shot.

Nick wakes up in the hospital and freaks out, causing the doctors to sedate him. When he comes to again, Wallis tells him that this stops now. She doesn’t know why he’s still alive, but he’s been given a second chance. She tells him that Helen is dead, and Lucas is unconscious. Nick leaves his room and frantically tries to find Lucas. When he finds him, the doctor tells him that Lucas may never wake up. Wallis leaves Nick alone in the room, and Nick sits down next to the bed. He asks if Lucas can hear him, but he can’t respond. He knows that he feels as though he loved Brendan more, but he tells him that he was drawn more to Brendan because he’s more like him, whereas Lucas is like Helen. He apologizes for everything that’s happened, and then leaves through the window in the bathroom. Wallis enters the room and sees that Nick has escaped, but also sees that Lucas is starting to move. Nick walks back to his house in the pouring rain and changes his clothes. He bandages his head again, puts on a cap, and goes to the bank. He withdraws all of the family’s saving accounts, putting the money inside a backpack. He also calls Owen and tells him to trace where the phone number from the picture came from. Owen runs it down and finds that it’s from a bar. Nick goes to the bar and asks the bartender where Billy is. He refuses to talk, so Nick beats him up. He offers him a wad of money, and again asks where Billy or any of his henchmen are. The bartender tells him where to find the junkie henchman, and then Nick asks him where he can find a gun.

Bones is sitting in his office when Nick shows up and requests guns. Bones is wary about selling them to him, since he doesn’t know him, but once he sees the money he starts to act more friendly. He shows Nick his secret stash of guns and lines out some pistols for him. Nick buys the pistols and a shotgun from him. Since he’s paying so much, Bones throws in the owner manuals for the guns and extra ammo. Before Nick leaves, Bones cocks a gun and tells him that he knows he’s there to kill Billy. Bones tells Nick that he’s Billy’s father, but he doesn’t care about him. He tells him that if he tries to ask where Billy is, he’ll shoot him. Nick leaves and goes back to his house, where he gets acquainted with the guns in his tool shed. He fumbles around with them, but eventually gets more familiar and comfortable with them. Nick then shaves his head, puts on Brendan’s leather jacket, and drives to where the junkie lives. He blasts open the door and finds him with a girl. He orders the girl to leave. Nick pistol whips the junkie and asks where Billy is. He tells him that he’s at the gang’s territory, which is an abandoned mental institution. He then has the junkie call Billy, who’s somewhere else doing something. The junkie tells him that Nick is still alive, and then Nick blows his brains out. Billy gets ready to move when Bones drives up. He says that he doesn’t care what happens to him, but he does care if it can come back to him. Billy, fed up, shoots Bones through the eye and steals his car.

Nick steals the junkie’s car and drives to the abandoned mental institution. He sees a goon sitting in a van outside, and so he rams his way through the gate and through the van. Nick enters the building with his guns and looks for Billy. While in a shootout with gang members, he blasts a goon’s leg off and then blasts his chest apart with the shotgun. He then chases down another gang member and blasts him through the window. He’s chased up the stairs, and he fires down at the remaining two goons. Billy shows up, sees the mess outside, and enters the building with his gun. While stalking Nick, a henchman walks into a room and doesn’t realize that Nick is on the other side of the wall. Nick steps on broken glass, and the henchman aims for the wall. Nick is quicker on the draw and blows his chest open. Nick eventually finds Billy in the chapel. They open fire on each other. Nick is shot in the chest, but shoots Billy in the arm and blasts off his fingers. Bodie shoots Nick in the back and in the neck. Nick shoots Bodie through the forehead, and then unloads his gun into Billy’s body. Nick grabs his neck and sits down. Billy, mortally wounded, tries to shoot Nick but misses with his last bullets. He then sits down next to him and tells him to look at what he made him become. Nick pulls out his last pistol and cocks it. He asks Billy if he’s ready, and then finishes him off. Nick drives back home, where he parks on the front lawn. He stumbles inside and watches home videos of his family. Wallis and other cops arrive at the house, and find him sitting on the couch. Wallis tells him that Lucas woke up, and is going to survive. The film ends with Nick watching home videos, leaving his fate ambiguous.