It is the 45th year of the Kurian Order. Lt. David Valentine is a proud member of the Wolves, an elite fighting force dedicated to regaining control of Earth. But a disastrous battle against the enemy has left more than half his company wounded or dead - and Valentine himself facing a court-martial.

Resigning his position, Valentine accepts an offer to become a Cat, one of the stealthy warriors trained to spy on and go toe-to-toe against the Reapers. Val's first mission is to enter the Kurian Zone and investigate the threat of the Twisted Cross, a strike force of alien-human hybrids possessing the skills of combat veterans and the hunger of the Reapers.