Cold Deck, Hot Lead by J. T. Edson

In this game, the winning hand is the one that holds the gun! A cardsharp with a conscience, Frank Derringer comes to the crooked town of Tribune, Kansas, looking to even a score or two. But after cheating the cheaters who robbed a good friend blind in a fixed game, Frank's escape doesn't go exactly as planned -- especially after he hooks up with a sharp-shooting lady named Martha Jane Canary, better known as "Calamity." True to her moniker, Calamity Jane's soon leading Frank into a hail of gunfire that's surrounding a dead man's dying words and a fortune in stolen gems. Now, stripped of the one edge they've both always had -- the advantage of working alone -- Frank and Jane are riding hell for leather into a deadly free-for-all and a killer's ingenious trap. And it'll take a sharp eye, a quick gun, and a strong dose of gambler's luck to keep them alive long enough to rake in the pot.