At the outbreak of the Civil War, and against his wife Rachel's pleadings, Captain Jesse Webb takes his beloved dog Squire to war as his regiment's mascot. By 1863, they're posted in Port Hudson, Louisiana. Here Jesse encounters his old rival for Rachel's hand, Colonel Hampton Lafayette Marsden, who'd killed Jesse's brother in a duel a few years earlier. Here, too, Squire kills a fighting bulldog in self-defense. The bulldog's owner, Aaron Blevin, conspires with Marsden against Squire and Jesse. In exchange for Squire, Blevin's daughter Giselle promises to have an "affair" with Jesse, designed to ruin Jesse's honor and marriage as Marsden's revenge for losing Rachel to him. When Rachel unexpectedly arrives at the garrison and Blevin captures Squire, trouble for both of them ramps up. Squire's life hangs in the balance; Jesse's marriage is on the line. Will Rachel forgive Jesse's "affair" and for losing Squire? Will Squire survive his ordeal and find his way home while the Union army battles the Rebel garrison?