Based on the 2014 non-fiction journalistic account written by Mitchell Zuckoff with the Annex Security Team. The film tells the harrowing story of the attack of the CIA Annex in Benghazi, Libya, on September 11, 2012, which killed four Americans. After the invasion, an American Special Ops team is sent to the Annex to protect the lives of those still alive who were caught within the compound.