A black flag whips in the early-morning breeze. Planted in the middle of a rocky hill a few hundred yards south of the mud-walled compound where the Afghan commandos have taken shelter, the flag’s message is clear: ISIS is here, waiting.

The mission of the commandos of Afghanistan’s First Platoon, First Special Operations Battalion is straightforward: Find the ISIS fighters and take them out. The soldiers are eager to take on an enemy that has killed many of their own, beheaded and blown up local villagers and driven countless people from their homes.

Pakistan, the source of many of the foreign fighters, lies a few miles away, over the denuded chocolate-colored mountains that stair-step up from the hill to snowy peaks. Mud-brick compounds, abandoned when fighting escalated here in Afghanistan’s Nangarhar province last summer, dot the valley floor. There is no movement except for the flag’s whip. No farmers tilling their fields. No one walking. The stillness is unnerving.

An order crackles over the radio: time to go. The soldiers move out across the rolling valley floor, searching one compound after another. To the west they can see their comrades from Third Platoon doing the same. The Afghan army and national border police are to follow behind, holding territory the commandos have secured.