If you wonder why modern combat stress wounds the psyches of some of America's soldiers, I suggest that "The Hurt Locker" will bring you up to speed.

Director Kathryn Bigelow's riveting film also examines the phenomenon of war as an addiction.

It centers on the three men who make up an Army bomb squad in Iraq. When an improvised explosive device (IED) or other booby trap is discovered, their mission is to defuse it or, that failing, safely detonate it. It is a tension-filled job in which failure means instantaneous transfer to the "hurt locker," i.e., death.

Specialist Owen Eldridge (Brian Geraghty) is young, confused and a little bit afraid. Sergeant J.T. Sanborn (Anthony Mackie) is a cautious professional, a by-the-book soldier. Like Eldridge, his most earnest wish is to survive the remaining 38 days of the team's rotation in and around Baghdad.

The squad's newest member is Staff Sgt. William James (Jeremy Renner). He comes aboard after the previous leader is killed by a bomb.

Renner enjoys cigarettes, heavy metal, jokes and, yes, the challenge of matching wits with a deadly enemy. But he disdains protocol and is prone to taking chances. He makes his teammates so nervous that at one point they consider whether to kill him without waiting for an IED to do the job.

"The Hurt Locker" was written by former journalist Mark Boal. It's based on his observations while embedded with an Army bomb squad in Iraq. His is a no-frills, straightforward screenplay. No one discourses on the morality of war. There are no Hollywood war-movie stereotypes among the characters. There are few of the down-time valleys that are said to separate adrenaline-laced spikes in the graph of combat-zone life.

Instead, Boal and Bigelow forge from one tense bomb-disarming or combat episode to the next, defining their characters more by what they do than what they say.

In this movie it's an urban war, fought mostly in the city's littered streets and wrecked buildings. Like the soldiers, we nervously look for a grenade around every corner, an IED under every Humvee, a rifle barrel in every dark and shattered window.

We watch as the tension and lethal fighting grind away at the bodies and minds of the soldiers even as it beckons some of their number into the fray like a drug. For them, war provides a high that's far more seductive than the appeals of civilian life and domesticity.

Performances by the virtually all-male cast are uniformly satisfying, though Renner's portrayal of multi-layered Sgt. James is a standout. "The Hurt Locker" seems likely to be in the running when Academy Award time next rolls around.

The Hurt Locker
3-1/2 stars
Showing at Grandin Theatre. Rated R for violence, language and gory images. 90 minutes.