You are the Master Chief, a real life super soldier helping Earth in their great push into infinite space. When the ship you are on is attacked by the Covenant, a group of aliens bent on destruction and conquest, you are forced down to the surface of an artificial planetoid. It is up to you to fight your way through Covenant forces to retrieve your commrades, but a force on the planet unknown to either you or the Covenant has been set free once again and forces you to fight not only your enemies, but those you once called friends as well. No small feat... even with an attractive AI construct in your head!

Also, get ready for the multiplayer experience you've been waiting for. This game takes combat to a new level, becoming one of the most popular multiplayer games in years!