Charles Richardson, John Heard is a civil servant in his early thirties, working in Salt Lake City's Department of Development. A depressed and impetuous romantic, he drinks on the job and laments his former lover, Laura, Mary Beth Hurt, an administrative assistant in the office's filing department. Though their brief affair ended over a year ago, Charles remains obsessed with Laura, who has reunited with her husband Jim, a log-home salesman. He tells his younger sister, Susan, and his best friend, Sam, Peter Riegert, that he intends to win Laura back.
In nonlinear flashbacks, Charles reflects on his affair with Laura and its swift disintegration, marked by jealousy and possessiveness: after he asked to marry her, Laura distanced herself. Following their breakup, the two briefly met in the parking lot of Laura's stepdaughter's school, but their meeting devolved into an argument in which Laura proclaimed to Charles that he has an "exalted" view of her that is not grounded in reality.
Consumed by his obsession with Laura, Charles frequently parks outside her and Jim's A-frame house, and at home constructs a miniature replica of it, complete with figurines and furniture. Sam, who is unemployed and staying with Charles, grows worried over his obsessive behavior. Meanwhile, Charles copes with his eccentric mother, Clara, Gloria Grahame, who is consumed by suicidal ideations, as well as his incredulous stepfather, Pete, Kenneth McMillan.
Charles learns that his coworker, Betty, Nora Heflin, has remained friends with Laura since Laura quit her job at the office. He casually attempts to court Betty, though his efforts prove unsuccessful as his feelings for her are not genuine. Charles visits Jim's custom home building company with Sam, the men posing as a gay couple under the guise of wanting to purchase one of Jim's houses. Jim allows Charles and Sam to view his home, shocking Laura, who returns during their tour. Jim explains to a visibly rattled Laura that Charles and Sam are lovers and potential clients. While Jim converses with Sam, Charles approaches Laura in the kitchen and hugs her. The four have drinks together in the living room, during which Charles startles Jim by proclaiming that he is in love with Laura, leading Jim to force the two men out of the house.
Weeks later, Charles is remorseful for his outburst, and decides to have dinner with Betty to distract himself. Charles is enlivened when he learns from Betty that Laura has again left Jim and moved into an apartment on her own. After retrieving Laura's phone number, Charles arrives at her apartment with a bouquet of tulips. Laura is ambivalent about his arrival, and wary of resuming a relationship with him given their past and the current tumult of her life. The two argue, and Charles eventually bids her farewell.
That night, Charles returns to his home and throws the A-frame replica dollhouse in the garbage, declaring that he is finally done pursuing Laura. Weeks pass as winter transitions into spring.