before dawn. master sergeant bryan leads his elite troops and afghanthgr eration. med to the main base dismantle, get out of the vehicles, started a vantsing towards this cluster of houses this small village. >> i never like this part. >> no. >> they can see us coming. >> reporter: the ground is littered with bombs left by isis and the going is as slow as it is dangerous. every building, every room, every door could be rigged with explosives. >> the troops have just moved into a whole series of compounds, in other words houses, that they're trying to clear. they're coming across a number of ieds every time they go into some of these buildings so they've got to be super careful. they're also wary there could be isis fighters inside there. >> ied. >> there's more here as well. >> reporter: every man knows all too well that death stalks their every move. more than 2,300 american troops