The game takes place in the year 2552, where humanity is locked in a war with the alien Covenant. Players control Noble Six, a member of an elite supersoldier squad, when the human world known as Reach falls under Covenant attack.

Originally formed in 1964 as the "Noble Five"…

And the soul said

Aye, aye, aye, aye hear the hound dogs moan

Aye, aye, aye, aye now that Floyd is long gone

Aye, aye, aye, aye now that Floyd is long gone

There's a full moon now

The moon was shinin' bright singing

Aye aye aye aye aye