Murphy's law
(Book)

"Murphy's plans for semi-retirement with his newfound love, Sally, are put on hold when he is called back to action by his boss, William Burke, who is a special assistant to the president. Counterfeit money is turning up in banks all across the west and could threaten the American economy and stock market if left unchecked. Leaving Sally at his Washington home, Murphy heads west to pick up the trail of the counterfeit money. The investigation spans months, during which time Murphy encounters Mary Kate Ritchie, a rising star in the cattle industry, outlaw Johnny Ringo, and a mysterious Japanese diplomat named Kyoto, who claims to be learning the American cattle business firsthand in the west. Along the way, Murphy is also aided by his old friends Apache Chief Ten Moons and his son, Two bears. Chasing his quarry across unforgiving mountains and deserts, Murphy is at his deadliest as he closes in on the man behind the scheme that threatens a nation" --from the publisher.