The novel takes place in the neighborhood of Bottom, in the city of Medallion, Ohio—a place which, at present, is a golf course for rich white people, but which used to be a thriving black community. In the 1910s, there is a man living in the Bottom named Shadrack. In 1917, he goes off to fight in World War I. He witnesses great violence in Europe, and returns to the Bottom a broken man. Shadrack then proposes a holiday for the people of Bottom: National Suicide Day. Every year, he walks through the streets, ringing a bell and yelling. At first, the people of the Bottom ignore Shadrack, but eventually, National Suicide Day becomes an accepted part of the calendar.
Another resident of the Bottom is Helene Wright. Helene was born in New Orleans, and raised by her grandmother, who taught her to be pious and moral. As a young woman, she married Wiley Wright, a cook. Wright brought Helene to live in the Bottom, and together they had a daughter named Nel. Helene quickly acquired a reputation for being a highly respectable woman, and she raised her daughter to behave the same way. When Nel is a young girl, Helene takes her back to New Orleans to visit her grandmother Cecile (Nel’s great-grandmother). On the train ride to New Orleans, a racist train conductor shouts at Helene, but Helene only responds by flashing him a dazzling smile. Nel notices that the black people sitting in the train are glaring at Helene for her deferential behavior. Nel resolves never to let any black man look at her this way. In New Orleans, Nel and Helene arrive too late—Cecile is already dead. Instead they briefly meet Rochelle, Helene’s mother, who is a prostitute and shows no affection or concern for Helene or Nel.
Another resident of the Bottom in the early 1920s is Sula Peace, a girl with a strange birthmark, shaped like a stemmed rose, on her face. Sula lives in a house that’s nearly the opposite of Nel’s: big, chaotic, and full of people. Sula is largely raised by her grandmother, Eva Peace, an old, one-legged woman, and her mother, Hannah Peace. Eva was married to a man named BoyBoy, who left her after she’d given birth to three children: Hannah, Pearl, and Plum. Eva devoted herself to raising her children. One winter, she left town for months, and when she returned she had only one leg, but plenty of money. (It’s rumored that Eva allowed a train to cut off her leg in order to collect an expensive insurance policy.) Eva’s youngest child, Plum, went off to fight in World War I. When he returned, he was ragged-looking, and seemed to have become addicted to heroin. Overcome with grief and love for her child, Eva doused Plum with kerosene while he was sleeping and set him on fire, burning him alive. Hannah, Eva’s eldest child, always sensed that Eva was responsible for Plum’s death.
By 1922 Sula and Nel are twelve years old, and have become good friends. Sula protects Nel from bullies in the city, and they have a similar loneliness that makes them close. One day, Sula and Nel go down to the Ohio River to look for boys to flirt with. By the river, they find only Chicken Little, a young boy. Sula dares Chicken Little to climb a high tree with her. Reluctantly, Chicken Little follows Sula up the tree. Then they climb down, and Sula swings Chicken Little around by the hands as he laughs. Suddenly, as Nel watches, Sula’s grip slips and Chicken Little flies out into the river. He disappears underwater and doesn't resurface.
Terrified that they’ve killed Chicken Little, Sula and Nel run for help, and to see if anyone witnessed the accident. The nearest house is a shack that belongs to Shadrack. Sula runs inside, where she finds Shadrack. Sula tries to ask Shadrack if he saw what happened on the river. Before she can finish, however, Shadrack says “Always”—which Sula interprets to mean that he did witness the accident. Sula runs out and Nel comforts her, noticing that Sula’s belt is missing. A few days later, Chicken Little’s body is found in the river. Sula and Nel feel guilty, and are frightened that they’ll be punished for their role in the child’s death.
In 1923, Hannah Peace is burned alive, for reasons that nobody can understand. In the days leading up to her death, she confronts Eva about killing Plum. Eva doesn’t deny what she did, but explains that she couldn’t stand to see someone she loved so much in pain. A few days later, Eva sees Hannah standing outside the house, her dress on fire. Without hesitation, Eva pushes herself through the second-story window of her house (trying to protect Hannah) and falls to the ground below. Both Eva and Hannah are rushed to the hospital—Eva survives her fall, but Hannah doesn’t survive her burns. Before she’s taken off to the hospital, Eva notices Sula, quietly watching her own mother burn. Eva comes to hate Sula because of this.
In 1927, Nel marries a handsome man named Jude Greene. Greene is ambitious and dreams of working on the New River Road—the big road that, white contractors claim, will one day link the Bottom with communities nearby. At their wedding, Nel and Jude are deeply in love and can’t wait to start a family. Following the wedding, Sula leaves the Bottom and doesn’t come back for ten years. During this time, Jude and Nel have several children. Meanwhile Sula goes to college and travels to the great American cities, looking for love but only ever finding men who want to sleep with her.
When Sula returns to the Bottom in 1937, she goes to visit Eva Peace. Sula accuses Eva of cutting off her own leg to get an insurance policy. A few weeks later, Sula calls officials at a nearby nursing home, and they come to take Eva away. Sula reunites with Nel, who’s still married to Jude, though she’s not as happy as she used to be. Nel is overjoyed to be reunited with her old friend. When Sula greets Jude, Jude is immediately fascinated by her. Shortly thereafter, Jude begins an affair with Sula. One afternoon, Nel comes home to find Jude and Sula in bed. Jude tells Nel that he’s leaving her, and within a few days he’s left, without Sula, to live in Detroit. The people of the Bottom come to despise Sula—they know that she’s slept with Jude and sent Eva away from her family.
In 1940, Sula becomes seriously ill. Nel, who hasn’t seen Jude or Sula in years, decides to go see her old friend. Nel demands to know why Sula broke up Nel’s marriage and destroyed their friendship. Sula responds that she’s strong and independent—she can do whatever she wants. She also asks Nel, “If we were such good friends, how come you couldn’t get over it?” Furious, Nel leaves Sula, and Sula dies shortly thereafter.
After Sula’s death, a frost comes to the Bottom, followed by a wave of disease. In January 1941, Shadrack walks through the streets, celebrating his annual National Suicide Day. He thinks back to long ago, when a young girl with a “tadpole” shaped mark (whom we know to be Sula) ran into his shack. He remembers taking the girl’s belt and whispering “Always,” meaning that the girl would be fine, in spite of her strange birthmark.
To Shadrack’s surprise, dozens of people walk behind him, yelling and cheering for National Suicide Day. Together, they walk all the way to cliffs overlooking the river, where they survey the supposed “New River Road”—in reality, a dirty pile of bricks that’ll never amount to anything. Disgusted with the hypocrisy of white businessmen, the people of the Bottom hurl stones at the road. Suddenly, a piece of the cliff breaks off, and dozens of people fall to their deaths in the river below.
In the final chapter of the book, set in 1965, Nel is a middle-aged woman. She goes to visit Eva Peace, who is still living in a nursing home. Eva asks Nel why she killed Chicken Little. Nel, shocked, insists that it was Sula, not she, who killed the boy. Nel runs outside the nursing home, where she sees a cemetery. She finds the graves of the Peace family, including Sula’s grave. Nel realizes that she’s missed Sula all these years, though she thought she’d been missing her husband. She cries out for her old friend, but no one can hear her.