Although they were at first happily married, Susan and Lorenzo Xavier Vega have slowly grown apart over five years of marriage. Larry, a chemical engineer at Finlay-Vega Chemical Company, is so busy perfecting a new insecticide that he often neglects his lonely wife. One night, when Susan's idle rich cousins, Millie and Henry Opdyke, insinuate that Susan deserves a more luxurious home with separate bedrooms, Larry suddenly announces that he has been asked to test his new product on a two-year-world-wide field trip and suggests Susan join him. When Henry calls Larry a selfish schoolboy for considering such a disruption in domestic life, a fight between the couples ensues. After the Opdykes leave, Larry admits that he picked the wrong time to talk about the trip, but then suggests Susan is becoming as conceited as Millie, prompting Susan to complain about Larry's bad habits and long work hours. Distraught by the turn in their relationship, Larry leaves to sleep in the study, while a tearful Susan remains in the bedroom. When a brisk wind draws her to the window, Susan watches as beautiful colored lights shimmering in the sky transform into the figure of man resembling Susan's movie idol, James Mason. As the figure walks into her bedroom, a terrified Susan rushes to the study, explaining that she is "scared" by a ghost. Larry assumes Susan has come to apologize and agree to join him on the trip to rekindle their love. The next day, when Susan tells psychiatrist Dr. Edward R. Winter about a guardian angel who appears only to her, the doctor thinks her obesession with Mason has caused the hallucination and sends her home. Later that day, after the angel appears repeatedly, Susan mentions him to her father, Charles Y. Bewell, a consummate drinker, who explains that Susan's mother's side of the family was rumored to have had guardian angels, while his side of family was known to see spirits. Later that day, when the angel warns Susan that her marriage is on the rocks, she asks why he looks like James Mason. The angel tells her that he looks that way because she wants him to, just as Larry's angel would appear in the form of his film idol, Ava Gardner. One morning, when Susan finally tells Larry about the angel, the scientist wants evidence of the angel's existence and laughs at his wife's behavior. That evening, when the angel causes Susan to behave strangely, Larry decides to take his wife out for dinner and a movie. Later, at the theater, they watch the real James Mason onscreen playing a brusque lover in pursuit of reluctant blonde leading lady Marilyn Maxwell. Susan is so enamored with Mason, she imagines herself as Marilyn, finally relenting and falling into Mason's arms. When the angel appears before her at home that night, Susan makes an obvious pass at him. Happy that her fear and resentment have turned into admiration for him, the angel takes the opportunity to tell a story about a wife who loves her husband, despite his ugliness, because she only sees his golden heart. He then suggests that Susan join Larry on the field trip to save their relationship. Susan is insulted that she must acquiesce to Larry, but the angel reminds her that she is only following Millie's snobbish lead. Later, when Larry announces he will leave in the morning for a two-day trip to Yosemite for work, Susan offers to go. Early the next morning on the drive to the park, Susan questions Larry about his job for the first time and discovers that he believes his work will help control insects in all countries, thus providing opportunities for people around the globe to prosper. Once they arrive at the park, Susan, an inexperienced camper, breaks the tent stake and instead attaches the tent to the car bumper. Soon, Larry attempts to drive supplies down to the water, causing the tent to collapse, and then watches as his bumbling wife baits a pole with a canned sardine, but then easily catches fish for their dinner. That evening, after Larry serenades his wife on an accordion, the happy couple retires to the tent where Larry zips Susan into her sleeping bag. Soon, however, a screeching owl trapped in the tent terrifies Susan, who begs Larry to solve the problem by leaving a lantern on to alleviate her fear. After Susan asks how to let air into the tent, Larry instructs her to pull a rope to open the window. Susan then accidentally pulls the boat rope, inflating the huge dingy in the tent, crushing Larry and Susan in their beds. Early the next morning, Larry, frustrated by his wife's antics, assigns her to row the boat while he collects water samples. When Susan tries to free the boat from a branch, she accidentally punctures it. As Larry salvages his equipment while the boat sinks, he yells harshly at his wife, who decides to return home as soon as possible. Resolved to intervene, the angel switches Larry's insecticide potion with pure talc so that his experiment will fail when company owners Bill Finlay and Clinton come to review the product's potential as an insecticide. When Larry discovers that the mosquito larvae are indeed still alive after application of the spray, he dejectedly walks away from the experiment. Susan finds him alone and tells him she believes in his research and will work right beside him. After the owners conduct another trial and find the solution works even better than expected, a pleased Larry accepts Susan's offer to continue on their two-year field trip together and her promise to learn more about waking up early and living outdoors. As the couple kiss, the angel walks into Larry's body and Susan falls in love with her husband all over again.
