Soldiers shoot at an unseen enemy in Afghanistan in a scene from "Restrepo."

A powerful new documentary about the war in Afghanistan opens Friday at Sundance Cinemas. For family and friends of Sgt. Josh Brennan in the Madison area, "Restrepo" is especially meaningful.

Brennan, 22, was killed in October 2007 in the Korengal Valley in a remote part of eastern Afghanistan, where much of the heaviest fighting in the war (and a high number of U.S. casualties) occurred. The film includes footage shot on the day Brennan was killed in a nearby village.

For Brennan's father Mike, a Madison police officer who lives in McFarland, "Restrepo" offers valuable insight into the events leading up to his son's death. It also provides a window into what life was like for Sgt. Josh Brennan and his fellow soldiers in the valley.

"For me, it's good to be able to see the area there and see who those people are," Mike Brennan said. "Just experience what it was like there."

For most of his childhood, Josh Brennan lived with his mother in the state of Oregon but spent his summers in the Madison area with his father. Family and friends of Josh Brennan plan to see the movie together on Friday.

The film was made by journalist and author Sebastian Junger (best known for his book "The Perfect Storm," later made into a 2000 movie with George Clooney) and Vanity Fair magazine photojournalist Tim Hetherington.

The two filmmakers embedded with members of the Second Platoon of the 173rd Airborne Brigade's Battle Company for more than a year, from May 2007 to June 2008. Josh Brennan was part of Battle Company's First Platoon, which conducted many operations alongside the Second Platoon in the valley.

In a phone interview, Hetherington said he's been gratified by the reaction of soldiers and their families to the documentary.

"For their loved ones, we've heard that the film has therapeutic benefits, because I guess it's a keyhole through which they can view the soldier's experience," Hetherington said. "Soldiers may be good at fighting, but they may not necessarily be good at communicating what they go through."

While his son was at a different camp than the one featured in the film, Mike Brennan said that "Restrepo" gave him a better understanding of the conditions that the soldiers were operating under. They often went without electricity or running water, ate pre-packaged MRE's (meals ready to eat) every day, and went up to a month without showering. And they patrolled a mountainous region where Taliban fighters had the high ground, and would constantly shoot into U.S. camps.

"Most people don't realize how much they were sacrificing," Brennan said. "When you watch that movie, boy oh boy. Not only to live under those conditions but to be shot at an average of three times every day, it's just unbelievable. You just wonder how more of these guys don't end up getting killed."

The ambush during which Josh Brennan was killed occurred during a weeklong operation dubbed Operation Rock Avalanche, a multi-pronged offensive intended to flush Taliban insurgents out of hiding and into open combat with U.S. forces.

In "Restrepo," the audience sees a firefight in which one of the members of Second Platoon is killed, devastating the rest of the platoon. The next day, the platoon enters a village and provides security for a U.S. colonel, who arrives by helicopter to warn tribal elders to stop firing on U.S troops.

Not seen in the film, Mike Brennan said, are the members of the First Platoon, including Josh, who were hunkered down outside the village providing additional security.

It was later that day that the First Platoon was attacked by about 22 to 25 Taliban forces, Mike Brennan said. Five U.S. soldiers were hit, including Josh, who was wounded in the chest. He was taken by helicopter to receive medical help and later died.

"Restrepo" is an apolitical film, focused solely on giving audiences the experience of what it was like to serve in Afghanistan. But Hetherington said that, as forces in Washington argue about drawing down forces next year, he hopes it will spark audiences to have a discussion about the future of the war.

"The film speaks a lot to the military, but it also speaks to the civilians," he said. "The film has a real capacity to bring people together to have that discussion, if people can accept to hear each other out. That discussion is important at this crucial time."

The film plays in Madison only through Wednesday. Brennan said he hopes people see it to get a better sense of what soldiers went through and what kind of help some of them may need once they return home.

"Some of these guys have got post-traumatic stress disorder, some guys have got traumatic brain injuries," he said. "I hope that the movie helps people understand these guys that are coming back, and why they are the way they are."