I am a Grisham fan but this is not his best work. If there is such a thing, I would call this a boring page-turner. You keep turning the pages expecting it to get better but then you get to the end and realize---that was it. I mean it has all the nuts and bolts of a solidly written piece of fiction but there is just no spark to it, nothing clever or surprising. After I'd turned all the pages, I blinked several times and turned off my kindle - surprised that it was over because it never quite got off the ground. The characters are one-dimensional and there is no real connection to them. Like the heroine in Gray Mountain, the female lead in this book is totally vanilla. You're not rooting for her or against her as there is little depth or character development.
* some spoilers The plot is laid out early in the book - there is a corrupt judge colluding with some thugs to skim money at an Indian casino. To expose the corruption, there are a few individuals trying to blow the whistle on the judge to collect cash under the whistle-blower statutes. The whistle-blowers submit a complaint to the agency that investigates rogue judges and an investigation begins. These facts are known early on. The problem is - that's the entire plot. There are no twists or turns it goes in a fairly straight line from corruption complaint to indictments with few surprises along the way. There is also a huge loose end as we never find out what happens to one of the characters who was falsely imprisoned for murders he did not commit. Since this character is a main focus in the prequel, the failure to tie up that loose end is irritating.
All in all - it is just an uneven effort. A disappointing novel from an author from whom we all expect better.