Desert Hearts is set in 1959. Vivian Bell (Shaver), an English professor at Columbia University, travels to Nevada to establish 6-week residency to obtain a divorce. She stays at a guest house for women waiting for their divorces to be finalized, owned by Frances Parker (Lindley).
Vivian meets Cay Rivvers (Charbonneau) a free-spirited sculptor to whom Frances is a surrogate mother. Cay works at a casino as a change operator in Reno, and is ending a relationship with Darrell, her boss, because as she put it, she "allowed (her)self to be attracted to his attraction" for her. When Vivian arrives, Cay notices her, and tightly controlled and elegant Vivian in turn is taken aback by Cay's boldness and lack of concern of what others think of her. Cay reveals that she has had relationships with women in the past. Frances notices that Vivian is becoming a bigger part of Cay's life and resents her for it, afraid that Cay will leave her and she will be alone. When everyone attends an engagement party for Cay's best friend Silver, Cay drives a drunken Vivian to Lake Tahoe afterwards and kisses her. Vivian returns it passionately and is so surprised by her response that she begs Cay to take her home. When they return at the ranch in the early morning, Frances has had Vivian's bags packed and a taxi waiting for her, furious (wrongfully assuming) that she has seduced Cay. Cay leaves the ranch immediately and Vivian endures the rest of her stay in a hotel casino.
After some days, both Cay and Vivian are clearly muddled and hurting. Cay goes to visit Vivian at her hotel and they make love and begin an affair. With Vivian's impending finalization of her divorce, they must sort out the future of their relationship, Vivian afraid of what people will think of her, and Cay unsure of what she would ever do in New York City. Frances and Cay are brought together, and Cay admits to Frances that Vivian has "reached in a put a string of lights around her heart". As Vivian is at the train station to take her back, she convinces Cay to discuss coming with her just until the next station.