You wake up from your cryopod (a pod that virtually freezes you so you sleep without ageing). The Covenant, an alien alliance, is trying to take the precious cargo. You fight your way to an escape pod with the cargo, an advanced artificial intelligence named Cortana. You land on an unknown object called a Halo Ring (an device built to kill all life within a certain radius). You must fight the Covenant as you try to stop the Halo Ring from detonating and killing all life for lightyears. This game came out in 2001 on the Xbox and PC.
All About Halo 