In the last cutscene of the Halo 3 mission Floodgate, the message left by Cortana explains to Master Chief and the others that there is a solution to stop the flood on the other side of the Portal without lighting the 6 remaining Halo rings. I’m well aware the “solution” is the Ark and the new Halo ring, but how could Cortana have possibly known about either of those? She was with Gravemind since the end of Halo 2, so how does she now about the Portal, the Ark, and Installation 04 B?
apparently the gravemind has the memory of the past graveminds (confirmed with his extensive knowledge about the forerunners and the things he’s said on the last mission), and he probably knew quite a bit about the ark. So I guess Cortana somehow got a hold of that info.
You answered your own question. She had come into contact with the Gravemind, who knew that the key to the destruction of the Flood was beyond the portal.
> You answered your own question. She had come into contact with the Gravemind, who knew that the key to the destruction of the Flood was beyond the portal.
But she said the Gravemind wasn’t aware of that solution behind the portal… And since it wasn’t in Halo 04’s databases (343 Guilty Spark would have known about it) maybe it was at the Construct at Halo Reach?
This is actually brought into question in the reprint of First Strike. In the Adjunct section of the book, there is a short story about a new reporter who managed to get her hands on Cortana’s message. She begins to theorize what Cortana was talking about when she said she had a solution to the Flood and mentions the possibility she knew about the replacement Ring and perhaps she meant the Ark itself. She then has a third theory but it’s not explicitly stated. Instead she gets excited and books a flight to Earth to investigate this third option. Most likely it will tie into the next series of novels or maybe even Halo 4.
From how I understood that, Cortana learned about the Ark from the Gravemind since he has the collected knowledge of all Flood, past and present. And I believe that Cortana was smart enough to figure out that the Gravemind would head for the Ark to seize control over it in order to permanently deactivate the Halo rings in the Milk Way galaxy.
So I think that her solution was this plan:
The only two Flood populations at that time were on Delta Halo and High Charity. Those on Delta Halo can be ignored because there is no way for them to leave the ring anymore.
The Flood on High Charity, which includes the Gravemind, will head for the Ark. The Ark basically serves as bait for the Gravemind.
Knowing the Master Chief, Cortana counted on him firing the replacement ring for installation 04 to wipe out all the Flood outside of Delta Halo, which was what ultimately happened.
> The only two Flood populations at that time were on Delta Halo and High Charity. Those on Delta Halo can be ignored because there is no way for them to leave the ring anymore.
I do not know if it is possible for any of the forms or really how it happens, but flood crash land onto the battlefield in Halo 3’s final mission. Therefore, I would not discredit the abilities of the flood to shape shift and have an ability to travel between worlds… what the circumstances are I have no idea and can only speculate, but I don’t think its too far of a leap to say they could accomplish that…