Spanning the twentieth century, 'Cottonwood Saints' chronicles the lives of a New Mexico woman and her son, Michael. Margarita Juana Galvan was born in a lumber camp in 1913 and is brought up like a little princess in her grandparents' hacienda. In contrast, Margarita's adult life is spent in depression-ridden Las Vegas, New Mexico. Told through Michael, Margarita's story embodies the challenges faced by an intelligent, independent-minded girl maturing in a man's world. Margarita and her family's lives intersect with the prominent events of the century: the influenza pandemic of 1918, the rise of the Ku Klux Klan, the Great Depression, and World War 2. Based on the life of Guerin's mother, 'Cottonwood Saints' connects the lives of the poorest citizens of New Mexico to the local power structure. The story ends after Michael, who became a priest, must leave his order in disgrace, and with the burial of Margarita in 1991.