This story is based in the early 1800's as parts of the Louisiana Purchase is opened up to white settlement. Immigrants from Europe begin to settle on the wild Missouri River as the young United States of America begins to transfer defeated eastern Indians onto the wide open plains. In this mix of cultures of western European Immigrants, displaced eastern Indians, and war loving plain's Indians is placed the most unlikely of hero, Mr. Matthew McDonald.
Matthew McDonald is an American born Scotsman who makes his living by fighting Indians and selling scalps. McDonald has been taught from birth on how to hate. As a young man he was taught the way of the feuding clans of Scotland. The McDonald clan have sworn revenge upon the Campbells who with the English army had attacked the McDonald glen; killing men, women, and even the McDonald children as the king had ordered the wholesale extermination of the McDonald clan.
The old Scottish feud spills over across the cold Atlantic as McDonalds and Campbells continue an old family tradition of fighting on American soil. The fight soon turns cockeyed as Matthew McDonald falls for the beautiful but deadly Widow McGregor whose maiden name just happens to be Campbell.
Matthew with his pockets full of gold and silver travels back towards civilization upon the Missouri River and finds a group of poor immigrants who have gambled everything on their farms and are about to lose their land because the government suddenly requires all land payments to be made in gold or silver. It is desperate times for the immigrants who gamble everything on this stranger passing through who knows where to find gold out west in the Spanish city of Santa Fe.
Matthew McDonald must lead a party of these greenhorn immigrants, which includes Campbells and the ill tempered Katy McGregor through the bloodthirsty Osage Indians, past the unpredictable Kiowa and right into the midst of the fearless Comanche Indians. The immigrants bet everything on a trip to Santa Fe and the gleam of Spanish gold. Matthew the loner can count on no one except his trusted mule which has been named unceremoniously, King George.
Feuds and family fights abound as McDonald and the Campbells join ranks and make war on eastern Indians, the plains Indians, the American Army, the Spanish Army, and anyone else who gets into the way of these desperate Scotsmen. In the midst of the gun smoke and barbarian behavior, Matthew McDonald and the beautiful, good cooking, ill tempered, Widow Katy McGregor find true love upon the plains.