Ground Control: Dark Conspiracy is a 2000 expansion pack to the real-time tactics video game Ground Control. Developed by Massive Entertainment and High Voltage Software, it was first announced in August 2000 by Sierra Studios. Later in October that year, Sierra further announced that the pack would be included free for new purchases of the original game, the decision having been made to add extra incentive to buying it; existing owners were also entitled and merely needed to apply via online form, also included as a hard copy in specially-marked boxes.