Sam is the black onion seller in 1880s Green Lake. He touts the healing powers of onions, citing his donkey Mary Lou as evidence: he claims that she's nearly 50 and never gets sick because she eats only onions. Nobody is sure if they can believe him, given that Sam himself is only twenty. Aside from selling onions, Sam also makes a number of tinctures and ointments out of onions meant to cure all manner of illnesses and ailments. Even Doc Hawthorn uses Sam's cream to cure balding. Sam is gregarious and appears to be loved by all. He and Miss Katherine form a friendship and then a romance when he offers to fix the dilapidated schoolhouse for her. When there's no more to fix at the schoolhouse, Sam kisses Katherine in the rain, insisting it will fix her breaking heart. However, because Sam is African-American, the kiss is illegal and the townsfolk riot. Sam and Katherine attempt to escape across the lake to Sam's secret onion fields, but Trout Walker's motorized boat is inescapable. Trout shoots Sam in the water, which puts a curse on Green Lake: no rain falls until Stanley and Hector, 110 years later, set things right. Katherine tries to avenge Sam's death by killing the sheriff, who wanted to hang Sam.