Detective Jane Rizzoli, having survived her encounter with The Surgeon, is brought into an investigation of a married couple who have been brutally murdered. The case takes a turn for the worst when Rizzoli can't help but notice similarities between the crime scene and the work of The Surgeon's in the first book. Maura Isles is finally introduced as the new Boston Medical Examiner. However, The Apprentice is about Rizzoli's struggles with the emotional scars left from her showdown with Warren Hoyt, as well as the arrival of the mysterious FBI agent Thomas Dean who keeps usurping her authority.
The best thing about Gerritsen novels, aside from a great plot, are that her characters always come across as fully fledged people, warts and all. They manage to have lives outside of their work and Gerritsen weaves these elements effortlessly within the main case. The Apprentice is equally as good, if not better than it's counterpart and I look forward to reading The Sinner.