Set in the Texas/Mexico border country, a desert made lush through human will, The River Beyond the World spans nearly half a century in the lives of two very different women and their families.

Luisa Cantu is chosen by the shaman in her Sierra Madre village to join him in an ancient fertility ritual more powerful to some of the villagers than Christianity. At first honored by her role, she begins to understand its burdens, and she flees the village and the confusing demands of her eccentric aunt and walks through the Mexican desert toward the Rio Grande.

She finds work in the Texas border town of Rio Paradiso as a housemaid for Eddie Hatch, a woman of strong opinions and a narrow world-view. The two women begin an intimate battle of wills as Eddie asserts her place of privilege while Luisa, subtly but stubbornly, risking the loss of the spiritual power she knew as a girl, tries to assert her own will.

By turns mystical and mannered, comical and deeply affecting, their story moves through decades of change, across sexual, social, moral, and spiritual divides, until the women's complex relationship reaches a painful moment in which they must decide what matters and what doesn't.