 You are Master Chief, John, SPARTAN-117. You are the most efficient piece of military equipment designed. When you are defending the planet Reach, a training ground for other SPARTANS and marines just as you trained there, the Covenant, a race of creatures that are aliens to Earth, whose first message sent to the human race was "It is our gods  will to destroy you", overwhelm the planet s defenses and "glass" the planet(use all their fire-power to destroy whatever is left of the planet). You are on the Pillar of Autumn, one of the smaller ships of the UNSC forces that left Reach. It makes a blind jump into slipspace (and warp that forces the ship into an alternate reality, allowing it to go to places faster using coordinates) where you find the massive ring structure,Halo, looming before the Pillar of Autumn. The Covenant (who followed the Pillar of Autumn through slipspace) use all their power to destroy the Pillar of Autumn. You are forced to leave the ship and take a life pod to the only place that may actually be safe, the ring... You continue to venture the ring with whatever UNSC forces survive the devastating crash landing of the life pods. You discover the horrifying secret of why Halo is there and how to escape the ring world. But the Covenant are cunning and more advanced, and they never give up, not even if it means sacrificing themselves...