The outpost they are building is at a village called Wanat - deep in a remote and isolated Afghan valley surrounded by the mountain passes insurgents use to infiltrate from sanctuaries in Pakistan, as CBS News National Security Correspondent David Martin reports.
Just four days later it would come dangerously close to
Apache helicopter pilots recorded video on gun camera tapes obtained by CBS News -- a furious fire fight, buildings in flames, and the only officer still alive on the ground calling for help.
"Be advised, we're in a bad situation . . . Need you to come in hot immediately," said the soldier on the ground.
The enemy is so close the Apaches will have to lay down their canon fire within 10 meters of the American position.
The soldier on the ground said, "I know it's high risk, but we need to get these guys off of us."
The pilot responded, "You got to be kidding me."
More Taliban are shooting down on them from those buildings. The Apaches make run after devastating run. They also come in firing their cannons, but the Taliban keep shooting back.
A desperately needed medevac tries to get in through the maelstrom, but instantly becomes a target.
Medevac pilot: "We're taking fire. We just got hit in the lower belly just to the north side of the aircraft."
The Apaches clear away a landing zone for the medevac.
Finally reinforcements arrive, and the tide of battle turns.
The battle took place a year ago in a valley that is now controlled by the Taliban. And it has triggered an investigation into why the 49 men of 2nd platoon were left so exposed so deep in enemy territory.
For much of its tour, the platoon was under incessant attack. Hunkered down at a base that was surrounded by high ground and could only be supplied by helicopter. Lt. Jonathon Brostrom set up a camera to record an assault on that base. When he was home on leave, he showed it to his father, retired Army Colonel David Brostrom.
"I was frankly shocked. They were getting attacked and probed every day, heavy attacks by enemy forces," said David Brostrom.
Brostrom's platoon and the other units fighting up and down the valley sometimes called in air strikes on houses from which they were taking fire.
"My son showed me that I said, you know, you just lost that village," said David Brostrom.
"We dropped 861 bombs with few questions asked," a senior commander is quoted as saying in a draft report for the Army Lesson's Learned Center obtained by CBS news.
They also fired white phospherous artillery at what they believed was a Taliban campfire. The rounds which were never intended to be used against personnel.
They were supposed to be protecting the population but according to the report the people "whose homes were being leveled and . . . Neighborhoods . . . Turned into battlefields . . . Saw no . . . Improvement in their lives and no real evidence of security."
Brostrom said, "You know, son, you need to get out of there." And he said, 'we are. We're moving to another location.'"
The new location - at Wanat - was supposed to be less exposed. But it was still in enemy territory.
David Dzwik was the sergeant of the platoon - 49 American and 24 Afghan soldiers. "I knew the mission had the potential of being quite hazardous," he said.
It was July and they were short of basic necessities. "The second day we were extremely low on water," said Dzwik. "When you start running out of water it's very hard to continue working through the heat of the day."
They had to take frequent breaks from preparing their defenses. Villagers knew what was about to happen.
Dzwik said, "a couple people came from the village, came up and said the enemy was going to attack."
Despite signs of an impending attack, unmanned surveillance drones which had been watching over the platoon were diverted to a higher priority mission.
A camera pointed at the sky recorded the first burst of machine gun fire.
"All hell broke loose," said Dzwik.
The first apache helicopters got there an hour and five minutes later.
Three-fourths of the Americans were killed or wounded.
"I pride myself on being able to push forward and kind of go through to do the job," said Dzwik. "For the first time in my career I actually stopped dead in my tracks when I came across the scene up there."
The Apache helicopter video shows American soldiers lying dead on the ground. One of them is David Brostrom's son.
"What did my son and what did those other sons die for?" asked Brostrom. "You have to do the investigation so this doesn't happen again."
Many of the soldiers on the videos are no longer alive. Nine were killed at Wanat.
Nine soldiers dead holding a piece of terrain which two days later the U.S. abandoned to the enemy.