McGee has fallen in love with a smart independent woman who falls ill, but it turns out she was shot with a dart, and murdered. He eventually tracks her death to a cult, who's duped members, male & female, are younger & generally more fit & better trained than McGee. He's accepted in their group as a useful idiot by pretending to be a lunk-headed fisherman looking for his daughter. Through luck, cunning, and being incredibly pissed off, he manages to take out the entire cult & it's leaders. One of the girls had fallen for him, and that part was pretty sad. Funny, he'd been given a special CIA number to call in case he was able to find the cult. The agents who had before looked at him as sort of a joke, now after seeing the carnage, regarded him warily like they would a dangerous animal.
Read this one & there's no going back.