Halo 3 WTFiction, By 1up.com (spoilers)

For anyone who needs to know something about the Halo games, this will lay the story out.

1up writes:
"So, you finished Halo 3. Then you finished it again on Heroic difficulty. Then you teamed up with a friend or three for a Legendary-difficulty playthrough. And at the end of it all, only one lingering question remains: What the hell just happened?"