After years of human civil war and growing political unrest, mankind's very future is threatened when our outermost colonies intrude upon the sacred worlds of the Covenant a fanatical powerful alliance of alien species. As the Covenant destroys world after human world only one soldier slows their advance a cybernetically enhanced "Spartan" supersoldier, the Master Chief. But as the incredible mystery of the Covenant's true ambition, and the secrets of his enigmatic past converge, then he will have to decide if humanity is a cause worth saving.