The player assumes the role of the Commander, who had been placed in alien stasis so they could make use of their strategic thinking via a brain implant. After the Commander is rescued by Central Officer Bradford, XCOM launches an attack on an alien convoy and steals an elerium core used to power the Avenger, an alien supply barge that has been converted into XCOM's mobile base. On the Avenger, the Commander has the support of Dr. Richard Tygan, a rogue ADVENT scientist who replaces the missing Dr. Moira Vahlen as Chief Researcher, and Lily Shen, who assumes her late father Dr. Raymond Shen's position as Chief Engineer.
