April 4, 2011 -- On a freezing Afghan mountaintop, with Pakistan close enough to touch, No Slack battalion, the 101st Airborne, began it's descent.
Watch 'World News With Diane Sawyer' for more on this story tonight on ABC
The Taliban were waiting in their safe haven -- a narrow mountain valley called Barawala Kalet. No foreign troops had ever dared to go there. With a five-hour barrage the Taliban were determined to convince the Americans to never come back.
Even though they were surrounded by gunfire, No Slack didn't budge. They gave back as good as they got, killing more than 100 of their enemy. But ammo was running low, and a tense voice on a field radio announced the cost of approaching the enemy.
"I have three casualties," said the voice over the radio. "I'll have more information when I get it."
Fire rained down from all directions. ABC News' Mike Boettcher was following Headquarters Company. Its captain, Ed Bankston, and Boettcher hugged a muddy mountainside, with the third platoon a short distance to the right and the first platoon to the left. All had wounded and dead.
Flying straight into enemy fire, Air Force parajumpers, known for their daring, attempted the first rescue. Their pilot was shot and their helicopter turned back.
"I have another casualty, they are all pinned down," said a voice coming from a radio transmission from the third platoon.
No Slack delivered a withering barrage of their own, temporarily quieting Taliban guns.
More Medivac helicopters poured into the valley. Seven medivac flights took place in two hours, although it was hard to get an exact number. When the clouds lifted, helicopters and bombers descended.
But in the chaos, there were miracles. Sgt. Matthew Mendez was saved by his chest plate.
"Took it like a champ," he said. "What happened? I got shot!"
"I got shrapnel in my a**," said another soldier. "My Tang bottle stopped it!"
Still, soldiers did not hesitate to run into fire to help a buddy.
"If you're not here, you'll never know," said Sgt. Joshua Frappier. "You can't really explain it to another person how you feel and what's going on in your mind."
"You got to put it out of your mind and keep going," said Sgt. Kellis Richardson.
Today, despite six dead and seven wounded, they are still going. Inch by inch, bullet by bullet.