But she knows what we'll say – what we've always said, when ever we got that text, those three words. I'm coming. I'm coming. I'm coming.”
-- Isa (chapter 1)

Importance: This is the opening chapter in which Kate texts Isa, Thea, and Fatima, giving them no details. She simply says that she needs them. The fact that Isa says they will all drop what they are doing and rush to Kate's side indicates a life-long commitment to each other that is actually out of keeping with their current relationship. They have not been together in years, but Isa knows they will all rush to Kate's side because she has called on them. The tone hints at something ominous, which will prove to be true.

As I picked up my case and followed Thea's retreating back, I had no idea that that one simple action had changed my life forever.”
-- Isa (chapter 2)

Importance: This is the first clue of...