The Dark Sector puts the player in the boots of Hayden Tenno, a covert agent who is sent on a dangerous mission to Lasria. This Eastern European city on the verge of destruction hides a deadly secret from the Cold War. During the mission, an unknown party attacks Hayden and implants the Technocyte virus - a brutal bio-weapon that makes his victim a brainless killing machine. But Hayden does find that the virus has given him new inhuman powers, and the task becomes a struggle for survival with new forces and a journey towards heroism.