So far the info is we are using Halo 4 so it is a Machinima and we are using the map of Ragnarok. More info soon
EDIT: Here is the storyline:
This is a time of war and despair for the men of Omega Posts Green and Yellow. Only three remain of the carnage from The Great Uprising in Ragnarok. One Alpha soldier and two Delta soldiers. Sergeant Smith of the Alpha Squad is the last of the original spartan project. Doc and Scorpion are all that remain of Delta Squad from the Spartan III Project. Smith has sent word into base for a new recruit. He received word that Private Polo was being shipped out today.