Nothing is actually WRONG with this book.
The idea is great, truly scary. I was tied in knots over Danielle's predicament. I kept thinking I'd burst, and wondering what I would or even could do in her situation. Would I lie? Would I pretend I was the killer? What could I do for my kid?

Yeah, it's a great idea. Terrifying and obviously thought-provoking.

However, none of it actually pulled me very deep in after the very beginning.
There's a mild case of insta-love, unresolved relationships (the big fat emphasis put on her career and partners that fell completely flat and none of very well explained. E.B.'s a phenomena; interesting to ponder upon, but ultimately a mystery).
Max's diagnosis, the biggest point of the book, is glossed over and unsatisfying. Danielle's sudden investigative skills were kind of unbelievable.
The crime-solving was really interesting, but somehow underwritten and sudden.
Tony's character was too Gary Sue-ish.

I don't know. I did enjoy the book, and the style wasn't bad, but I felt like it was awfully superficially written.