In a small suburban town, three close friends and wives - Deborah Bishop, Lora Mae Hollingsway, and Rita Phipps - embark on a day trip with their children's community center. Just as they are about to depart, they receive a letter from their acquaintance, Addie Ross, which shocks them to their core. Addie informs them that she has run off with one of their husbands but leaves it to them to figure out who it is. Each woman, now fraught with insecurity and suspicion, reflects back on her marriage, wondering if her relationship was the one that faltered.

As the day progresses, flashbacks delve into the lives and marriages of the three women, each highlighting their distinct insecurities and marital challenges. Deborah, a former farm girl and the newest member of their social circle, worries her war hero husband may find her too unsophisticated. Lora Mae, who grew up on the wrong side of the tracks, questions if her wealthy husband truly loves her or if their marriage was mere convenience. Rita, a successful radio writer, fears her career has emasculated her husband, a schoolteacher. As the hours tick away, the trio confronts their personal demons and the strength of their marriages, all the while pondering which husband has been ensnared by Addie's charms, leading to a day filled with reflection and revelation.