Ifemelu is a Nigerian woman living in Princeton, New Jersey. Her primary source of income for the past several years has been her blog about race and class, Raceteenth or Various Observations About American Blacks (Those Formerly Known as Negroes) by a Non-American Black, but by the time the novel opens she has decided to shut down her blog and move to Nigeria, where she has a job waiting for her at a women's magazine called Zoe. In fact, she has already made the necessary arrangements. She has broken up with her boyfriend, Blaine, sold her condo, and shipped her car to Nigeria—all of which surprises her friends and family. She has been living in America for ten years, and it seems to them like she is throwing her life away.
Ifemelu is determined, however. She visits Mariama African Hair Braiding, a hair salon specializing in black hair. This isn't Ifemelu's usual salon, which is closed while the owner is on vacation in Côte d'Ivoire. It doesn't take Ifemelu long to realize that she doesn't like the stylists at this new salon. Her stylist, Aisha, has two Igbo boyfriends in spite of the large pink sores on her arms that look like they might start to ooze at any moment. Irritated, Ifemelu attempts to read, then sends a brief email to her ex-boyfriend, Obinze, whom she affectionately calls "Ceiling" (a reference to how, when he touched her in bed, she couldn't see the ceiling, even though her eyes were wide open). She tells him that she will be moving back to Nigeria soon.
Obinze receives Ifemelu's email while he is stuck in traffic in Lagos. He is now a successful businessman in Nigeria and has a daughter, Buchi, with his wife, Kosi. He is amazed at the turn his life has taken and loves his daughter, though he is just coasting through his marriage, pretending to love Kosi. Ifemelu's email throws him, stirring up old emotions just as moving has for her. This prompts Adichie to take readers back in time, relating the story of Ifemelu's life. She is born in Nigeria, not far from the town of Nsukka. Her mother is a devout Christian who gets taken in by an overzealous church. Her father works for a federal agency until he gets fired for refusing to call his female boss "Mummy." He can't find work, and Ifemelu's family lives in poverty. Meanwhile, Aunty Uju becomes the mistress of the General, an important man with connections in Nigeria's ruling class. The General keeps Aunty Uju living in style, and Ifemelu's parents occasionally borrow money from Aunty Uju to pay the rent. In spite of these hardships, Ifemelu continues to excel in school.
Ifemelu and Obinze meet as teenagers. Originally, Obinze is set up with Ginika, Ifemelu's shy, quiet friend, but he pursues Ifemelu instead. Theirs is a good match. Both are excellent students, and both enjoy reading, though they don't always agree about books. Obinze's mother—a tenured professor at Nsukka University—encourages Obinze's love of books. Rumors circulate that his mother started a physical fight with another professor, but in reality the other professor (a male) struck her because he couldn't bear to be publicly accused of mishandling funds by a woman. This prompted her to take a two-year sabbatical in Lagos, where Obinze meets and falls in love with Ifemelu. Obinze's mother approves of their relationship. She is, however, concerned about them having sex, and when Ifemelu has a pregnancy scare, Obinze's mother gives them a lecture about contraceptives.
Obinze wants to attend the University of Ibadan because of J. P. Clark's poem "Ibadan." He changes his mind, however, when his mother suddenly collapses in a library. He decides to enroll at Nsukka University in order to be close to her, and Ifemelu joins him out of love. Unfortunately, their time at university is marred by the frequent teacher strikes that take place. Many students decide to transfer to foreign universities. Ifemelu is one of them. She takes the SATs and then enrolls with Ginika at a college in Philadelphia, Pennsylvania. Before she leaves, she and Obinze make a plan: he is going to come to America as soon as he graduates. He will find some way to get a visa. They will be together. Not long after she arrives, though, Ifemelu breaks off contact. Her life in America is hard—much harder than she expected. She has trouble finding work, and Aunty Uju, with whom she stays in New York the summer before moving to Philadelphia, has to work three jobs while she studies for her medical exams. Finally, Aunty Uju passes her exams. She becomes a doctor, and Ifemelu starts school.
Ifemelu's experiences in New York have left her wary, however. Her scholarship is only partial, and there isn't enough left over after tuition to cover the rent. She tries to find work in a restaurant or an office but keeps getting passed over—possibly because of her skin color. One day, desperate to pay rent, she accepts a "job" that involves "relaxing" a rich, insensitive tennis coach. He gives her $100 to have sex with him. Afterward, she feels dirty and cheap, and she's too ashamed to call Obinze or tell him what has happened to her in America. Instead, she goes silent and doesn't speak to him for years. Thankfully, she receives a real job offer shortly after the incident with the tennis coach. She is hired as a nanny for two children, Morgan and Taylor, whose mother, Kimberly, overcompensates at times for her privilege. It is a good job, though, and Ifemelu likes the kids in her charge. Morgan can be sullen, like a teenager, but obeys Ifemelu. Meanwhile, Aunty Uju and Dike move to Warrington, Massachusetts, where she works as a doctor. Things are beginning to look up.
Ifemelu begins dating Curt, Kimberly's cousin. Curt is white, well-to-do, and well-meaning, and he falls in love with Ifemelu quickly. He uses his connections to find her a job at a public relations firm in Baltimore. She gets her hair straightened for the interview, but the harsh chemicals in the relaxant cause her hair to start falling out soon after she gets the job. Ifemelu decides to stop straightening her hair and instead grow it out naturally. This prompts her to visit several message boards devoted to the care and maintenance of black hair. Her coworkers make a note of the change, but it has no effect on her career. Her life proceeds as usual until she runs into an old friend, Kayode, at a mall one day. He mentions that he has recently heard from Obinze.
In Part 3, the narrative shifts focus to Obinze and his life as an illegal immigrant in England. In spite of Obinze's excellent grades and upbringing, he is unable to secure a visa and is forced to work under the assumed identity of Vincent, using an Englishman's National Insurance number and paying him a thirty-percent cut of all earnings in exchange for this privilege. Obinze gets a job in a warehouse and starts saving up for a sham wedding, which will earn him citizenship. Before he can save up enough, however, the Englishman, Ibola, demands a forty-five percent cut and turns Obinze in to immigration authorities when he refuses. Obinze is arrested, deported, and sent back to Nigeria, which turns out to be a boon for him, because he goes on to become a very successful businessman in Lagos.
Part 4 shifts focus back to Ifemelu, picking up her narrative just after she breaks up with Curt. "There was a feeling I wanted to feel that I did not feel," she tells her friend Ginika by way of an explanation for their sudden breakup. Something was missing in her relationship with Curt. He didn't understand her experiences as a non-American black woman and was oblivious to the subtle little ways in which he himself could sometimes be racist. Once, he criticized a fashion magazine for only featuring black models. This was, if not the final straw, then the impetus for the breakup. It also inspired her to start her own blog, Raceteenth or Various Observations About American Blacks (Those Formerly Known as Negroes) by a Non-American Black, in which she referred to Curt as "The Hot White Ex." To her surprise, the blog takes off, and she begins receiving donations from readers who want to support her writing. Due to the popularity of her blog, Ifemelu is invited to give lectures around the country, and the commissions from these speaking engagements, in addition to the donations from the blog, allow her to quit her job and buy a small condominium.
Ifemelu reunites with an acquaintance, Blaine, at one of her lectures. Blaine is an assistant professor at Yale and writes a blog about race and popular culture. He and Ifemelu first met years before, on a train, while she was still dating Curt. She never forgot him, however, and is surprised to hear that he hasn't forgotten her, either. Their relationship progresses quickly, and Ifemelu moves to New Haven from Baltimore to live with Blaine. He's very supportive of her work, but his sister, Shan, is a sharp critic, not just of Ifemelu but of everyone and everything. Ifemelu learns to accept this. Around this time, Barack Obama announces his historic candidacy for President of the United States. Ifemelu is skeptical, at first, and prefers Hillary Clinton, whom she wants to become the Democrat Party's presidential candidate. Blaine, on the other hand, supports Obama. Sometimes, their different political views put strain on their relationship. One day, Blaine leads a demonstration in protest of the suspension of an African American security guard falsely accused of dealing drugs, but Ifemelu chooses not to attend. He doesn't speak to her for days. She packs her things and goes to visit Aunty Uju in Massachusetts. Nine days later, Blaine comes up to visit, and they reconcile.
Ifemelu and Blaine search for an apartment in Princeton, New Jersey. Ifemelu's writing fellowship is designed to give her as much time as possible to write and lecture, and she takes advantage of it. Her blog becomes even more popular and political. One day, she reads Barack Obama's book Dreams of My Father and decides to support Obama instead of Hillary Clinton. This brings Ifemelu and Blaine closer together, but only briefly. Ifemelu soon becomes dissatisfied with their relationship and longs for Nigeria. She breaks up with Blaine, shuts down her blog, sells her condominium, finds a job at a magazine in Lagos, and makes plans to move back to Nigeria.
Finally, the narrative catches up to the first chapter of the novel, in which Ifemelu sits in a hair salon and writes a quick email to Obinze. He writes back, thrilled to hear from her, but is crestfallen when she falls silent again. Only later does he learn that her silence was due to tragedy: her nephew Dike attempted suicide.
Ifemelu postpones her move to Lagos until Dike recovers. She spends the next several weeks with him, worried that he'll attempt suicide again. With time, she grows comfortable with the fact that he needs to spend time alone or with his friends. She later decides that it's time for her to move to Nigeria.
When Ifemelu arrives in Nigeria, it takes some time for her to adjust to living in Africa again. She has, as her friends tease, becomes an Americanah, and she must reacclimate to Nigeria. She works as a features editor at Zoe, a new women's website in Lagos. Her boss is Aunty Onenu (no relation). Ifemelu finds most of the work uninspiring and is very critical of the way the site is run. She notices things about Nigerian culture that she has never noticed before, such as how waiters only speak to men, assuming the men have all the money and power, and how the Nigerian film industry is even more misogynistic than the country itself. Whenever she talks about this with her friends, however, they say that she's Americanized. She bristles at this suggestion. One afternoon, Ifemelu sees a man who looks like Obinze. She sends him a text reading, Ceiling, it's me. He immediately calls her, and they arrange to meet that same day. Over glasses of mango-orange juice, the former lovers catch up, knowing, all the while, that they're going to get back together.
Their affair reinvigorates Ifemelu, making her feel safe and at home for the first time in years. It isn't perfect, however, and the peace and happiness she experiences with Obinze is quickly marred by the fact that she has to share him with his wife, Kosi. When Ifemelu demands that Obinze leave his wife, he hesitates, restrained by his sense of duty to his family. He has been coasting through his marriage for years, content with its passionless companionship, and finds it difficult to ask Kosi for a divorce. Furious, Ifemelu breaks up with Obinze, calling him a coward. She refuses to speak to him, ignoring his many phone calls and messages and spending more time with her friends. She even calls Curt and Blaine, wondering how they are. Then, seven months later, Obinze knocks on her door. "I'm chasing you," he says, repeating a line he used years before, when they first met. Finally, she lets him in, and the novel ends, leaving readers to presume that the lovers reconcile.
(The entire section is 2254 words.)