Mitch Nelson (Hemsworth), a US Army Captain with Operational Detachment Alpha (ODA) 595, is moving into a new home with his wife and daughter on September 11, 2001. Nelson had previously been assigned to staff duty under LtCol. Bowers (Riggle) but volunteers to lead ODA 595 into Afghanistan. CWO5 Spencer (Shannon) was scheduled to retire but volunteers for an additional deployment. After leaving their families, ODA 595 travels to Uzbekistan on October 7, 2001. After receiving a brief from 5th Special Forces Group Commander, Col. Mullholland (Fichtner), ODA 595 is selected to fight alongside the Northern Alliance leader, Abdul Rashid Dostum.
After covertly traveling aboard an MH-47 Chinook, ODA 595 arrives 30 miles south of Mazar-i Sharif, and meets Dostum. Six of the 12 members, led by Nelson, leave with Dostum to the mountains, while the other six remain in a fortified camp nicknamed “The Alamo.” Dostum is attempting to capture Mazar-i Sharif, a critical city in northern Afghanistan, from the Taliban. After several battles, Nelson accuses Dostum of acting carelessly with the lives of his men; Dostum replies that Nelson, and America, do not care for the future of Afghanistan, and are unwilling to sacrifice for it. The two reconcile, with Dostum telling Nelson about losing his family in the civil war. The remainder of ODA 595, led by Spencer, travels to the mountains to support the Northern Alliance. After several tactical victories, Dostum is making significant progress towards Mazar-i Sharif. Nelson reveals to Dostum that ODA 555 is supporting Atta Muhammad, another Northern Alliance leader who is Dostum’s political rival. Enraged, Dostum and his men abandon ODA 595.
Following Dostum’s departure, Nelson plans to take Mazar-i Shariff with just 12 men. Encountering heavy resistance, ODA 595 struggles to destroy Taliban weapons; Spencer is critically injured by a suicide bomber. Dostum returns, and the combined forces repel the Taliban and kill their leader. After Spencer is medivaced, Dostum and Atta Muhammad peacefully meet in a captured Mazar-i Sharif. Spencer ultimately survives, and ODA 595 returns home after spending 23 days in Afghanistan.