Doc is a ex-NSA spook, seemingly content with his life as a marine biologist, running a biological supply company. Unfortunately, he gets dragged into a murder mystery when a despised marina owner is found floating out in the water during a fishing tournament. Doc's friend gets accused of murder, and is surprisingly copacetic about it. In addition, Doc has to deal with his complex relationship with a woman tennis pro, and somehow he's also gotten on the bad side of a psychotic killer. So he keeps busy throughout, but maintains his bemused sense of humor.
Compared with the first book, Sanibel Flats, there's no international intrigue, and no apocolyptic finish. This also works fine for me.