The Big Finish — James W. Hall

It has been one year since Thorn Moss's son, Flynn, disappeared into the eco-underground, his only contact with Thorn a series of postcards chronicling his exploits. When a new postcard from Flynn arrives--with a plea for help--Thorn sets off for North Carolina to save him. But before Thorn gets there he's intercepted by a federal agent who tells him he's too late: Flynn had been acting as an informant for the FBI, and when his traitorous acts were discovered, he was summarily executed.

The agent proposes a scheme to catch Flynn's killer using Thorn as bait. Full of rage, Thorn agrees to the mission. Soon he's among a gang of eco-terrorists planning an attack on a hog-farming operation...only to realize that the trap the FBI's setting is not for Flynn's killer at all. It's for Flynn's partner, a woman who has her own dangerous agenda. Now, with her help, Thorn must unravel a deadly conspiracy that stretches far beyond this small Carolina town. And he will stop at nothing until justice is won...