Homer Smith, an African-American handyman traveling through the Arizona desert, unexpectedly finds himself at a remote farmstead run by a group of East German nuns. Led by the strict Mother Maria, the nuns initially employ him for minor repairs, but soon persuade him to take on the grander task of building a chapel. Homer agrees reluctantly, motivated by a mix of faith, pity, and an increasing sense of responsibility. Despite language barriers and cultural differences, Homer and the nuns form an unlikely bond as they work together to begin construction.

As the project progresses, Homer grapples with various obstacles including scarce resources and his own doubts about the scale of the undertaking. The local townspeople become interested in Homer's efforts, with some offering assistance and others remaining skeptical. While Homer's initial intention was to move on quickly, his growing connection to the nuns and their steadfast determination compel him to stay longer than he had planned. This transformative experience for both Homer and the nuns forms the foundation of their shared journey, which is marked by humor, tension, and moments of profound understanding.