Halo: the last rebellion
Not so long ago, the Covenant had fled the earth, leaving only the elites behind. Now, they attempt to work with the humans. The U.N.S.C. had started to lower their guard against alien attacks, and their use of Spartans. The O.D.S.T.s were used more often in wars, Spartans were now only used as a last resort.
Then, some Spartans began to change; they started to betray their fellow soldiers, eventually betraying their own superiors.
And that takes us to this day...
The Foundry. 9:23 Am. Epsilon squad's base.