Anyone here can give a summary of why anything is happening?
So: Q was working with Yayoi Kokuryou to avert the prophesied end of the world by awakening the ”god”, inside of Yume. They ensured this by giving her siblings for whom she would care for and give her a connection to humanity, and an adversary, them, to focus her anger on and awaken fully. However, Yayoi is a body swapper who wants the strongest vessel to possess and so has lured Yume to this specific place, the one where her journey into the Gray began, to perform the ritual to take Yume over. This was not part of Q’s plan and so Aikawa was betrayed. Yume foresaw this, hence why she was making her former agent, and Aikawa’s childhood friend tag along all this time so she could save her.
The wild card however, is Yume’s feelings for Nagomi which I think Aikawa and Yayoi both underestimate, and probably surpass Yume’s desire to save humanity.
And now: FIGHT!!!