Hey.
I'm awkward. Do you want to be awkward together?
...
That was nice.
(This is just the set-up for the story, so bare with me)
The story begins with the Chief drifting towards the Forerunner planet in the broken aft section of "Forward Unto Dawn". As he prepares for a crash landing, hundreds of Sentinals not unlike the ones from Onyx materialise in front of him. They destory his vessel, but the Chief makes it off alive and lands on the planet in the same fashion as the beginning of Halo 3, but sustains multipul injuries that render him barely able to move.
The next scene lets you take control of the Chief as he lays in a deserted area near a seemingly abandoned Forerunner structure as Cortana, who is at the end of her life, keeps him company. She slowly becomes weaker and eventually shuts down. The Chief then blacks out and wakes up briefly while being carried on the back of a vehicle. He soon finds himself inside, being nursed to health by a group of Forerunners. Cortana is also fixed and somewhat upgraded due to the Forerunner's extensive knowledge of AIs, but she loses most of her memory.
The Forerunner speak in a form of Latin (like in Ghosts of Onyx) to the Chief and tell him that their ancestors, who were the last of the Forerunners when the rings were activated, secured themselves on the planet and created an AI that was designed to never let them leave the planet until there is evidence that their sins were justified, and the Chief is this evidence. But soon the AI went rogue and, using the same methods as the Forerunners used on the humans 10,000 years before the Flood Wars, they devolved the captive Forerunner's society and forced them into slavery.
The group of Forerunners cautiously make contact witha high-ruling Sentinal and show it The Chief as evidence that the human race had survived, but the Sentinals want the Chief dead because they don't want the Forerunners becoming a huge empire once more, so the Chief has to join a Forerunner rebellion and find them a way off the planet.
The story would focus a lot more on the Chief personally, and his final stand against an aincient enemy.
Udig? I haven't read Cryptum so I dunno if this would even work, so just give me your honest opinions.