Worlds Colliding (Supernatural) Book Seven

The revelation of Castiel being controlled and manipulated into such things has shattered everyone involved.
Sam, Dean and Catty Winchester.
Ness and Bobby Singer.
And Octavia the Angel.
Catty also realizes that Castiel hadn't been the only one who had been manipulated and used by Crowley and Balthazar. She realizes what exactly happened, and she is willing to do anything to try to fix it, even while grieving Castiel and Octavia's deaths.
Dean is angry at Crowley and Balthazar. He is angry at Castiel for letting them get so far as to control him the way they had. He's angry that Octavia died. He's angry at everything. But when Bobby dies, will he continue to fall apart, or be there for Ness?
Sam is going through his Hell Wall that is crumbling, and Octavia's death. What remains of his Hell Wall comes in a shape that surprises him. It's not only Lucifer that he sees.
Ness has always been the level-headed one. The one to go to when you need help or advice. But when her father, Bobby dies, what will this do to her? Will she be angry, devastated or revenge-driven? Or all of the above?
What happens when Catty finds what she's looking for?
What happens when Ness gets her vengeance?
What happens when people that they think are dead don't stay dead?
And who else will they lose?