In this book Fox starts to investigate a cop, only to discover that his sister's abusive boyfriend has been murdered. Like most people, he can't help himself, and starts to investigate the crime himself. This bring him face to face with the complaints department himself and for the rest of the book he has to deal with them and their threat to his career, while still investigating the crime himself.
It's also worth noting that Edinburgh feels different to Rebus' Edinburgh. Fox's investigation leeds him to the "new shiny" Edinburgh that was built off borrowed money. Rebus's Edinburgh has always felt slightly grimier than this does.
In short, this book is a good read, but don't expect it to be like a Rebus read, or even recognise the Edinburgh it occupies.