The following version of this short story was used to create the guide: O'Neill, Joseph. "Rainbows." The Best Short Stories 2022: The O. Henry Prize Winners. Vintage Anchor Publishing, 2022.

Joseph O'Neill's short story "Rainbows" is written from the first person point of view of the protagonist Clodagh. Spanning several years, the short story employs both the past and present tenses. The following summary adheres to a linear mode of explanation and the present tense for the sake of clarity.

When Clodagh is 23 years old, she moves from Ireland to the United States to pursue a graduate degree in applied analytics. Feeling overwhelmed by New York City culture and the demands of her master's, Clodagh decides to audit an anthropology course. Almost as soon as she meets the professor, a classy and enigmatic Italian woman named Paola Visintin, Clodagh is enamored of her. Having heard from an American friend about mentors and mentees, Clodagh asks Paola if she can start meeting with her during office hours.

Over the course of the following two years, Clodagh meets with Paola intermittently at a café. During their meetings, Clodagh talks about her life, sharing all of her woes and questions with Paola. Although she believes that Paola cares for her, when Clodagh tells her about being sexually assaulted, the professor is callous and dismissive.

Some years later, Clodagh is still living in New York City. She has become a successful businesswoman. She is married to a man named Ian and has an 18-year-old daughter named Aoife. While Clodagh is away on a business trip, Ian discovers that their daughter is dealing with an interpersonal conflict. She tells her father that a boy names James Wang has been stalking and harassing her. When Ian tells Clodagh about the situation, she promises to resolve it when she returns home.

Although Clodagh plans on using her interrogative business style to extract the truth from Aoife, as soon as she sees her daughter, she softens. Without hearing Aoife's story, Clodagh calls the school and demands that they protect her daughter or she will pursue legal action. When James is suspended, the issue seems to dissipate.

Not long later, Clodagh visits the laundromat she has frequented for the past 10 years to collect her laundry. She is shocked when the owner tells her that her son is James Wang. Mrs. Wang no longer wants Clodagh's business because of what her family did to her son.

Although Clodagh contemplates advocating for James with the school, she decides against doing so. Expressing remorse, she feels, will only cause more trouble.

Shortly after Aoife leaves for college, Clodagh takes the train to Albany to see a client. On the trip back, she is shocked to see Paola. She suddenly feels ashamed and embarrassed. Upon further reflection, she decides to approach Paola. They share a few drinks together and catch up. When Clodagh tells Paola about Aoife and James's conflict, Paola is dismissive. She then launches into a diatribe about Irish- and Italian-Americans, bewildering Clodagh. Realizing her professor is a snob, Clodagh starts to pity her.

Back at home, Clodagh tells Ian she wants to go back to Ireland to see her brother. They have not been since Aoife was four. Shortly after they landed, Clodagh and her family saw so many rainbows, they stopped noticing them.