In Pakistan, Zahir Sharq convinces Gerald Baxter to put a gun to his own head. Baxter plays Russian roulette with his life to coerce Porter to talk. Porter begs Baxter to consider his family, and his appeal works. In a moment of clarity, Baxter shoots one of Sharqs guards and the two men escape.
Hugh Collinson meets with U.S. representative Frank Arlington in London. Collinson refuses Arlington's demand that the British government accept responsibility for the deaths of the American Marines killed in the fire missile incident in Afghanistan. Later, Arlington intimidates Collinson into releasing Porter and Baxter's rendezvous point to the Americans.
Former Special Air Service soldier Steve Andrews, in a coma since the 2003 hostage extraction, dies at a London hospital. Layla Thompson investigates Andrews' death and confronts Collinson about her findings: She has evidence proving Collinson killed the British soldiers in the Basra stairwell. Collinson wants Porter dead, Layla hypothesizes, to bury the truth.
En route to the rendezvous point, Baxter and Porter are attacked by the Taliban. Baxter is killed. Collinson arrives in Afghanistan to meet Porter. In an emotional confrontation, he comes clean about 2003; he shot his comrades in a moment of panic. Porter agrees to let sleeping dogs lie, just as Taliban forces launch an assault on their location. Collinson dies taking out the attackers, while Porter evades capture and flees.