Jeremy Renner's performance as Sergeant William James, who comes on board as the lead technician of a three-man squad after their previous tech is killed in the film's opening scenes. Their job is simple: respond to reports of IED locations, find the offending devices, and attempt to disarm them. What complicates things immediately is James' penchant for ignoring safety protocols and putting himself in harm's way, to the point where his squadmates Sanborn and Eldridge feel as though he disregards their safety, as well, for no clear reason.
In a typical Hollywood production, this all would've wound up with some cackling Iraqi bomb-making mastermind leading the group on a cat-and-mouse game through the dirty streets of Baghdad, but instead, Hurt Locker makes it clear that there is simply a never-ending stream of explosives that are placed around the city, left there by mostly anonymous bomb-makers. The bombs are chillingly impersonal, at least in intent, aimed as they are at the occupation in general, but of course James and his cohorts take a rather personal interest in the fact that the bombs could wind up ending their lives instantly.
Sanborn and Eldridge exhibit varying levels of the war-weary attitude that you'd expect to find in most modern war film, so it sucks for them that they have to deal with James, who is in love with war, or at least obsessed with the rush it affords him. Renner plays him as a force of nature: he has a calling, he intends to do it well, and anything beyond that is just a matter of wasting time. Even in his downtime he's sometimes portrayed as a kind of animal, coiled up in his room, listening to Ministry at ear-bleeding volumes, biding his hours until the next assignment. There's some kind of odd connection between him and Bodhi in director Kathryn Bigelow's Point Break; both are addicted to adrenaline, have found methods to obtain it, and aren't overly concerned with what happens to those around them when they're on the hunt. James isn't necessarily unfeeling, but his emotions seem to conveniently come online only when they serve to bring him another adrenaline rush. There's a moment halfway through the film where he smuggles himself out of his base in an attempt to confront the father of a boy he believes has been murdered, which ends up with him running through the dangerous Baghdad streets alone, at night.
It's James' connection with the boy that winds up being his closest brush with salvation, or some kind of attempt to break free from his perennially imminent self-destructive fate. The boy, who goes by the name of Beckham and attempts to hawk DVDs to the soldiers, bears no relation to James, apart from perhaps reminding him of his young son, but he treats him well, probably even better than he treats his squadmates. Later, he discovers his body in a warehouse where IEDs are constructed, waiting to be turned into a "body bomb", where explosives are placed inside the stomach cavity and the body is presumably left outside to draw attention before exploding. It's a weird moment, where both of the things he cares about--bombs and the boy--are conflated in a surprisingly concrete manner.
It isn't until his recklessness causes the shooting injury of a teammate that James is given a moment to pause and consider his actions. Or, perhaps more accurately, he's forced to come down off of his high--complete with the obligatory "showering while fully clothed" scene. Like any good junkie, though, his moment of calm doesn't last, and soon enough he's out in the field again, with the implication that that's where he's going to stay there until his luck finally runs out, in search of the elusive ultimate rush.
Apart from relatively minor quibbles, Hurt Locker is an astounding film, both because of its focus on an aspect of war-making that has never really been filmed before and its portrayal of a man whose addiction to war winds up pushing everything else in his life aside. Renner's heartbreaking monologue to his son late in the film winds up being as memorable as any of the explosions that occur before it, which says something about where the heart of this film lies.