With two tours of Iraq under his belt, Sergeant Dave Henley knows what modern war looks like.

But nothing can prepare him for the posting to Forward Operating Base Senzhiri, Helmand Province, Afghanistan.

This is a battlezone like he's never seen before. He's in charge of 1 Platoon, a ragbag collection of rookies who he must make into a fighting force - and fast.

But this is a brutal, unforgiving conflict which takes no prisoners.

Their convoy is ambushed on the way to the FOB, leaving two men grievously wounded - before they've fired a shot. Back at home, Dave's wife, Jenny, seven months pregnant, must try to hold together the fragile lives of the families left behind, who all wait for the knock on the door and the arrival of bad news...