Arma 2: Reinforcements brings to the Armaversum two new factions - Her Majesty's Armed Forces and private contractors.
Company team of British paratroopers patrolling the treacherous mountains in Zargabad's vicinity is ordered to battle the amassing guerilla warriors.
Private Military Company, ION, Inc. (formerly Black Element), successfully bid for a contract - codenamed Black Gauntlet - to provide security for a UN investigation team as they seek to piece together information regarding Takistan's abandoned nuclear weapons programme.