Going Dark (Thorn) by James W. Hall

Last adventure we learned Thorn has a son. In this one he has to help him survive his involvement with a group of eco-terrorists called ELF. Meanwhile, FBI buddy Frank Sheffield is preparing to prevent a plot against a nuclear plant.
Every time I open up one of his books I'm reminded about how cool James' writing style is. It is unique but still hard to pinpoint why, in a way John Sandford's style is. It flows very naturally and is a joy to read.
Thorn is cool as always, putting in a few good oneliners but never becoming a pastiche of the hardboiled hero.
Frank Sheffield steals the show here, though. He's a unique character with an original voice and a number of flaws (like his weakness for women). I hope we will see him around in the future.