I recall that in one of my blogs I wrote that Annabeth might be used as a bait. Going on to that, I think Percy might as well be manipulated by Melinoe to make him follow Gaea. Melinoe betrayed Hades in The sword of Hades by helping Ethan escape and she also manipulated Nico and Thalia by appearing as their dead mothers. So I think that Annabeth will be the sacrifice Percy will have to make (even though he can't afford to do so). I think she might (emphasis on might) die and Melinoe could appear to Percy as Annabeth and like Gaea had thought; she might be able to control Percy. Mars also mntioned that Gaea thinks she can control him and also Gaea did spare him, instead of Phineas.
Melinoe could still betray the gods, I mean she did it the first time. In the demigod files. Gaea might have recruited her again. She can be quite useful.
To see more of my theories on Annabeth- Click Here.
This is part II of this blog.Here.
Btw, what do you think of the new theory? Too impossible? Nah don't think so.