I love a good thriller, and I love when books take their time to reveal what exactly happened. This book is great at doing this - keeping the suspense almost all the way to the end. I just think it overdoes a little bit in the middle, in a way that you start to connect the dots a little bit too early. Other than that, if you don't think too much about what you're reading, it is a great thriller.
We learn in the beginning that Maddie is married to Ian and has a child named Charlie. But then the book keeps alternating between the past (to a time when they haven't even meet each other), a few weeks earlier, and the day it all happened. I would say that some chapters dedicated to the past are a little bit too boring (and I struggled to go through them), but they were important to understand the present, so I understand why they were there.
Overall, I would say this is a beautiful read if you like suspense and thrillers.