Driver (Dwayne 'The Rock' Johnson) hears on the radio that the bouncer he has just stabbed is still alive and is in a critical condition in hospital. He spins his car around and returns. Just like before, he coolly enters the building, walks up to his target, and takes him out.
'The Cop' (Billy Bob Thornton) also guessed Driver would be returning and chases him out the building. There's a shootout and Driver points the gun between his eyes. The Cop drops to his knees and closes his eyes, but Driver leaves him.
On the way out, Driver is chased by 'The Killer'. Driver is faster and has him in his sights, but just blows out his tires. The Killer retaliates by shooting Driver in the neck.
There are 2 targets left now. The Killer gets advice from Lily to wait and just go to the last name on the list.
The Driver returns to his family home and pulls the gun on his mother. He assumed that his step-father would have been the one that ratted him out, but he died a few years earlier and seems to have been innocent of that. His wound is stitched and he is back on the road for the last target - a travelling Evangelist. Again he listens to a sermon on the radio about past sins and consuming anger.
Driver approaches a large tent in the middle of nowhere, and steps inside to hear the Evangelist (Mr Eko from Lost). The Evangelist finishes his sermon nervously. At the end, they both walk down to the river. The Evangelist asks for forgiveness, and it seems he is the only one to have completely turned his life around. He regrets what happened - although he tried to stop the man who became the bouncer murdering Driver's brother, he still spent his take, and was only saved when he was locked up.
Driver spares his life and returns to the tent. The Killer enters and holds a gun to him, and starts to moan about how he had a tough childhood. Meanwhile Cicero is outside - and has pieced together the clues when she receives a report from CRASH which links all the snitches - they were all under the care of The Cop. Quite surprising really why it's taken everyone so long at Homicide to realise this.
The Cop walks into the tent and shoots Driver in the back of the head. So it was him who was behind the whole thing - and he shot Driver 10 years ago. The Cop tries to pay The Killer $1 dollar - the amount he wanted, and frames as a trophy, but he refuses.
The Killer phones Lily and tells her he is coming home. The Cop phones his ex-wife to tell her that everything will be ok now. In a flashback we see what happened - his ex-wife was the girlfriend of Driver's brother, and also one of his snitches. They planned it all together.
Suddenly Driver is back on the scene - the bullet hit the metal in his head and just left him with a bad headache. He shoots The Cop dead.
Cicero soon finds the body - but hides the evidence so that his family can keep his pension money.
The Evangelist gets up to deliver another sermon - this time about Forgiveness, as Driver takes his brother's ashes to the sea, and then gets back in the car to keep on Driving.
The Killer has a change of heart and can't let it go that he wasn't "faster". So he turns his Ferrari around and catches up to Driver. There's a big game of chicken where Driver's car uses the Ferrari as a ramp, and both cars are pretty well smashed up. They both get out with a few broken bones. The Killer forgets he has no bullets left and tries to shoot Driver. This time Driver has no pity and shoots him in the chest.
As he lies dying, Driver shakes his hand and tells him he did good, becoming a kind of father-figure to him. The Killer is finally content, and dies.
Lily learns that her husband has died, and gets out to the shooting range full of rage, ready for Driver 2.
Driver gets back in to his beat up car and soon enough is chased by about 20 LAPD black & whites. It's a much better final scene than the proper ending where he just checks himself in the mirror -- but I'm guessing they wouldn't have been able to explain the beat-up Chevvy. And the long final battle with The Killer took away from the real showdown against the true villain - The Cop.