This is the tenth book in Randy Wayne White's Doc Ford series. The events of previous books have gotten Doc into kind of a funk: he's drinking too much, not exercising much, and becoming an unreliable friend. But an old friend shows up out of the past: her husband has gone missing under strange circumstances, and he's been involved with a cult with a charismatic leader. But it turns out the charismatic leader is a fraud and has a psychopathic underling. So we're off to the races.
As usual, Doc Ford channels a good bit of Travis McGee, and sometimes it seems a little forced. Doc's friend Tomlinson is also along for the ride, and they pick up Frank, a private eye from New Jersey early on. The interplay between them is pretty good; unfortunately Frank won't be around in later books.
The ending is thrilling and satisfying, and I'm looking forward to reading the next one.