You are Conrad Hart, a graduate student and agent of the GBI or Galaxial Bureau of Investigation. While you were helping your girlfriend, Sonya, you noticed what looked like aliens had invaded the earth disguised as humans. Unfortunately, your discovery didn't go unnoticed and you were kidnapped and taken to Titan. Your memory was also wiped. However, you managed to stash some holocubes on yourself that may hold the key to getting your memory back and saving earth.
You must battle your way through seven levels, fighting aliens, replicants, robots and other agents to restore your memory and save earth. Along the way you will discover clues and items to help you in your quest.
Though this game has some elements of role-playing and adventure, it is foremost a shooter game, not unlike Doom or Duke Nukem.