Hard Rain Must Fall — Tony Masero

Rain. It never stops.
It just keeps coming, until it seems the whole of Yoma County will flood. One man rides out of that downpour. A man carrying a Colt on his hip and a mission in his heart. He is to find no warm welcome awaiting him at his destination.
Steven Arc is a backswood boy who grew up hard in the woods of Wisconsin with no more abilities than a quick wit and a sure-shot's eye. It isn't until he joins the 7th Wisconsin Iron Brigade that he finds a true home. But then, as luck would have it, this is 1860 and the country is preparing for Civil War.
Captured and imprisoned in the stinking prison pit called Andersonville, where savage gangs fight piteously over a crust of bread. It is only there that Arc finds out who his real friends are. But when that hell ends, that's when Arc's war really begins.
A ride down to a damp little town in New Mexico finds dark shades from the past lying in wait. Before the rain stops a river of blood will flow in the flooded gutters as old friends and enemies fight it out over a secret payload.