Following the defeat of the Taliban in 2001 Amir joined the Afghan Army becoming an officer. For the next five or so years he is involved in fighting the resurgent Taliban alongside American, British and other coalition soldiers. During an operation to capture a district in Faryab province, his friend Jawad and several other of his soldiers are killed in an ambush and he berates the Afghan Brigade Commander in front of other senior officers, including some from the coalition. Arrested on suspicion of sympathy with the Taliban he faces Court Martial until a US Marine who had been an adviser attached to the Afghan battalion defends him, producing evidence that the Afghan Brigade Commander deliberately suppressed intelligence because the Taliban were holding some of his family hostage. Amir is acquitted but is advised that many senior Afghan officers distrust him for what they see as a betrayal leading Amir to transfer to Special Forces where he is put in command of his own team.

On one operation in Helmand, Amir and his team are cut off and besieged in an old fort for nine days, forced to survive by eating snakes and lizards after their food runs out. Fortunately, just before their ammunition ran out a British force backed up by helicopter gunships and American bombers breaks the siege.

Amir went on to become a battalion commander for his last four years serving as the US started to withdraw troops and hand over responsibility to the Afghan Army.