Marines and Navy corpsmen of the 2nd Marine Expeditionary Brigade launched Operation Khanjar in southern Afghanistan on July 2, 2009. The goal of the operation, whose name translates into "Thrust of the Sword," is to drive the Taliban from its traditional stronghold in the volatile Helmand Province, a strategic supply route and fertile ground which yields 50 percent of the world's opium poppy — raw material for heroin. The 4,000 Marines, joined by 650 Afghan soldiers, left from camps Bastion and Leatherneck in the northern part of the province.

Catch the 'War Stories Classic: The Battle for Afghanistan,' Monday, July 27 at 3 a.m. ET

In August 2008, "War Stories" traveled to Helmand to embed with 2nd Battalion 7th Marines and the 1st Battalion 6th Marines — who preceded the Marines in-country today. "Helmand has been controlled by the Taliban for a while," said Capt. Matt O'Donnell, a company commander with 2/7 Marines, which was based out of Camp Bastion. "It's their heartland."

The 2/7 was tasked with clearing the area from firmly-entrenched Taliban as well as training Afghan security forces. "War Stories" documented the life-threatening conflict in an hour-long special, "The Battle for Afghanistan."

In Now Zad, located in northern Helmand Province, the Taliban threatened to kill the local population if they didn't abandon the town and proceeded to rig it with improvised explosive devices, or IEDs. In response, a company of Marines fought to reclaim the area from the enemy. "You name it, we did it," remembered Sgt. Ben Lanford, a squad leader in 2/7. "Small arms fighting, RPGs… IED threats… the engagements are very intense."

To the south of 2/7 in the Garmsir District was 1st Battalion 6th Marines, also engaged in blistering fights with Taliban resistance, who deployed IEDs and snipers in an effort to maintain their foothold.

"We came down into Garmsir, and got into a real fight, and it lasted there for almost a month of daily, almost conventional forces," said 1st Lt. Clint Harris, at the time a platoon commander with 1/6. "Then the enemy… started to switch back towards a true insurgency campaign like we were seeing in Iraq."

An added challenge for the Marines in Helmand today — and then — is the oppressive heat and spartan living conditions. When "War Stories" was there, temperatures soared to 115 degrees Fahrenheit, with little shade. The lack of electricity meant no air conditioning or cold beverages. Creature comforts were at a bare minimum. "You just pour water all over yourself," explained Cpl. Justin Van Houten, describing how they showered. "If you have soap you use it, but usually don't."

Despite all these challenges, Operation Khanjar is proceeding according to plan. The Marines have reached their objectives and like their predecessors, are prepared to accomplish their mission at any cost.