It's very difficult to discuss the plot of this book, without giving too much away - something I hate seeing in a review. The only thing to say is that it takes the three strands mentioned above, and blends them together, gradually bringing all the connections together.
If you've read Sam's previous books, Blood Ties and Unspoken, you'll have an idea of what to expect, both in style, and pace. Everything that I've enjoyed with those previous books carries on in this one, there was no disappointment.
Sam's books are all thrillers - they are fast paced, and very difficult to put down. However, they don't rely on being plot driven books - the characters within are always interesting and believable. As well as wanting to know where the story in general is going, I also find myself wanting to know what's going to happen to the characters too.
If you have already enjoyed Sam's previous books, I would strongly advise this one. If you haven't, and you enjoy emotional thrillers, I would strongly advise that you give one a try!