Monday, March 4, 6:30 a.m.
Editor's note: In our Behind the Scenes series, CNN correspondents share their experiences in covering news around the world.
BAGRAM AIR BASE, Afghanistan (CNN) -- The mortars continue to fall behind us. So do bombs from the jets trying to hit them.
Apparently the search-and-destroy team we're moving with has gone undetected. It's hard to believe. We seem like such a fat target moving up the narrow valley. Snow-covered mountain peaks soar over us, studded with green pine trees. You feel like you're in one of the back bowls at Vail, Colorado.
Only the mortar blasts and the occasional distant heavy machine-gun fire shatter the illusion. The soldiers are moving lightly armed. We left the 50-caliber machine guns and 60 mm mortars behind with the troops guarding the mouth of the canyon. It's just too much to carry.
I fear we'll be spotted any second and all hell will break loose. We stagger on, slipping on ice-covered rocks. Fall down, get up, keep moving, gasping, swearing. Maybe a shot will end the anguish.
Just put one foot in front of the other. We're talking basic locomotion. Around me soldiers collapse, resting their backpacks for a moment on a nearby rock. Their packs weigh three times mine.
We pass an abandoned stone house. Now we could be in New Mexico, except for the old Russian anti-aircraft gun and cannons beside the house. Engineers go to work destroying the guns. We leave them behind, happy in their task.
Suddenly a hand motion calling for the unit to stop is passed back: Those on point find footprints in the snow. They're not from military boots. And they're heading in the opposite direction. Automatically we all scan the terrain in front, behind and above. We see no one but ourselves. But I can't shake the feeling we're being watched.
As the force moves deeper into the valley, squads of men peel off and set up positions to make sure no unfriendlies try to crawl up our backs. The mountain with the al Qaeda cave is looming in front of us. But like victims of some cruel trick, we never seem to get any closer.
Scott McWhinnie, my cameraman, pushes on with the forward unit. I fall behind but I can see soldiers staggered up the canyon. "How far to the cave?" I ask as I pass them.
"About 200 meters."
"How much farther?" I ask the next group.
"About 500 meters."
What is this, I wonder? -- some kind of joke?
"Just around the bend," two other soldiers say. Why am I not surprised that it's not there when I turn the corner? I slog on. Head down. Lift one foot, put it in front of the other. That's all I'm thinking.
Suddenly a rock tumbles from the ridge above, startling me out of my trance.
It's then I realize I've made one of the dumbest and potentially most fatal mistakes you can make in a war zone: I'm alone -- separated from the unit.
There's a momentary sense of panic. More rocks trickle down from above.
The voice in my head wants to know who -- or what -- is causing them to slide.
My brain conjures up all sorts of nasty possibilities. I try to stop it from wondering there.
What now? Did I somehow miss the advance unit and here I am pushing into enemy territory by myself?
Maybe they're just ahead around the next bend. Then again, maybe not.
I can go back, of course, but how far?
The only thing I know for certain is that I'm alone.
Or am I?
Coming: The next step in the uphill battle.