When human remains are found on the site of an Afghan charity water supply project, Leo, Nikki and Jack are sent to the war-torn region to establish if they are the remains of a British soldier who vanished five years ago, suspected of being murdered by Taliban forces. Amidst ruthless Taliban attacks and a dangerous, alien culture, Leo develops a life-changing relationship with a charity worker, as the team grow suspicious of a British security firm’s torture of captured Taliban fighters. But when a forensic breakthrough changes the course of the team’s investigation, it triggers a chain of events that puts them all in imminent danger.