XCOM: Enemy Within is the expansion to the 2012 Game of the Year award-winning strategy game XCOM: Enemy Unknown. Enemy Within adds an array of new abilities, upgrades, and weapons to combat new enemy and alien threats. This expansion pack also introduces new maps, new tactical and strategic gameplay, and new multiplayer content, providing a fresh new gameplay experience.

Threatened by an unknown enemy, Earth€s governments unite to form a secret paramilitary organization, known as XCOM, to combat this extraterrestrial attack. As the commander of XCOM, you control the global defense team and its resources in a battle against the terrifying alien invasion. You control the fate of the human race by creating and managing a fully operational base, researching alien technologies, planning combat missions, and controlling soldier movement in battle.