Book twenty-eight in the Reacher series, 'The Secret,' picks up right after the events of 'No Plan B.' He's still riding the rails and gets off in a small Maine town where a local man was killed in a hit-and-run. Reacher senses it wasn't an accident, and the victim's sister, a former FBI analyst, convinces him to dig deeper.
It spirals from there. The town is a front for a pretty sophisticated counterfeiting ring, but the product isn't money—it's high-end pharmaceuticals. Fake cancer drugs, to be specific. The operation is brutal and tightly controlled. The main villain is a woman named Eloise Vartan, who runs a private equity firm as a cover. She's not a physical threat to Reacher at all, but she's cold, intellectually arrogant, and views the deaths caused by her fake meds as just a cost of doing business. Her security is handled by a truly nasty ex-Special Forces contractor who acts as her enforcer.
The dynamic is interesting because Reacher has to dismantle a system, not just a person. Vartan thinks she's insulated by layers of legality and distance, but Reacher, being Reacher, just plows straight through all of it. The final confrontation is less about a fistfight with her and more about systematically destroying her entire operation while she watches, which for her is a fate worse than death.