James W. Hall's novels about would-be hermit and reluctant hero Thorn are always among the finest of Florida crime fiction. But Going Dark, the 13th in the series, is one of his very best, a breathless thrill ride with a brain — and heart.The novel opens with the bizarre death of Leslie Levine, a young biologist studying the population of American crocodiles living in the canals that surround the Turkey Point nuclear power plant south of Miami. When she was a young girl, Leslie lived near Thorn's Key Largo home with her mostly useless mother. The kid was almost as prickly as Thorn himself, and with good reason, but the two formed a quiet alliance over fishing lures and saltwater. Years later, she had recently returned to visit him, and he was proud not just of her achievements but her fierce concern for Florida's disappearing wild.When she dies, Thorn is still trying to recover from the events of the last novel, Dead Last, in which he found and then lost adult twin sons he never knew he had. When his best friend, private investigator Sugarman, tells him about Leslie's death, Thorn can hardly believe it, but he's too far into his funk to pursue it. A couple of months later, a massively muscled stranger shows up at Thorn's house, asking questions about the cistern and solar power system but refusing to identify himself. Annoyed, Thorn asks Sugarman to trace the stranger's license plate.It turns out he is Cameron Prince, the man who was working with Leslie when she died. Prince is a member of one of those classic Florida families: His grandfather was a prominent Miami businessman who made a bundle, his father was a wastrel who spent it all, and Cameron is left with a well-known name and not much else. He's a body builder who runs a private gym at his Coconut Grove home, and when Thorn goes there to look around he discovers a photo of one of his sons, Flynn Moss.Thorn and Flynn haven't spoken to each other since the events of Dead Last, but Thorn's parental instincts kick in and he goes looking for Cameron, and Flynn. That takes him to Prince Island, out in Biscayne Bay. Once it was the Prince family estate, but now it has returned to its wild state, "marooned in another warp of geologic time. As harsh and brutish as the terrain was, to Thorn this was the only Florida that mattered, the landscape that kept his heart in tune, that hummed in his marrow."But Thorn's trip there is no idyll. He's soon a prisoner of a small cadre of members of the Earth Liberation Front, a radical environmental group. Among those members is Cameron, but they're camped on Prince Island not just because he owns it but because it allows easy access by water to the Turkey Point nuclear plant — for which they have an alarming plan.While Thorn is trying to gain control of that situation, his friend Frank Sheffield, an FBI agent nearing retirement age, is dealing with Turkey Point security from another angle. Its internal computer network has been hacked, and he's working on the case with another federal agent, the seductive and ambitious Nicole McIvey, and the nuclear plant's security chief, the extremely obnoxious Claude Sellers. As Thorn's case converges with Sheffield's, everyone's alliances and motives come into question and the danger grows. Along the way, there will be electrocutions, a python attack, some steamy sex and a stunning display of federal bureaucracy at its worst. And the novel's climactic scene is enough to give anyone who lives within a few hundred miles of Turkey Point nightmares. Even after that, Hall has a few surprises up his sleeve.Colette Bancroft can be reached at [email protected] or (727) 893-8435.