The following version of this book was used to create the guide: Winslow, De'Shawn Charles. Decent People. Bloomsbury Publishing, 2023.

After visiting her brother Herschel in New York city, a woman named Jo Wright returns to her fiancée Lymp's house in her home town of West Mills, North Carolina, a segregated, rural community that Jo has returned to after many years of living in the city. Upon arriving home, she is greeted by Lymp's son, Nate, who explains to Jo that Lymp's half-siblings—Marian, Marva, and Laz Harmon—have been murdered in cold blood in their nearby mansion. When Jo learns that the police suspect Lymp of the crime and have taken him in for questioning, she resolves to investigate the case on her own, convinced that the mostly-white police department will not expend resources on exonerating her fiancée if they can pin the murders on him. Jo visits Angela Glasper, Marian's former secretary, and begins seeking information about the days leading up to the Harmons' deaths; she learns that the Harmons were involved in several disputes across town, including ones with Eunice Loving, Savannah Russet, and Ted Temple. Jo begins her querying by visiting Eunice at home and asking questions about Marian's relationship to Eunice's son, La'Roy; Eunice avoids Jo's questions and rudely insists that she leave.

As Eunice reels from Jo's intrusive arrival at her doorstep, she goes over the events of the past several weeks and struggles to forgive herself for having sent her son, La'Roy, to Marian's pediatrics center in order to receive "conversion therapy" for his homosexuality. When La'Roy arrived at Marian's house, she instructed two brothers, Terrance and Troy Russet, to begin beating La'Roy until he renounced his sexuality, but the Russets refused to do so. Although Eunice drove to Savannah Russet's house after the events to beg Savannah not to speak publicly about what occurred, both Eunice and Savannah had public confrontations with Marian and Marva Harmon, respectively. As the town begins to prepare for the Harmons' funeral, Eunice struggles to motivate La'Roy and her husband, Breezy, to attend the funeral with her; Jo also struggles to convince Lymp that he must make an appearance at the funeral. Savannah Russet, meanwhile, struggles to prepare herself for the funeral because she is in grief over the death of her best friend Marva, experiencing withdrawal from the Valium that Marva used to supply her, and steadily falling behind on her tax payments.

After the funeral concludes, Jo confronts Savannah and begins interrogating her about the deaths of the Harmons, which eventually makes Savannah so uncomfortable that she leaves. Savannah reflects on how ostracized she feels by both the Black and white communities in West Mills because her father, Ted Temple, renounced her when she married a Black man named Fitz. When Savannah returns to work after the funeral, Ted comes into the store where she works and offers condolences, but the pair spar over Ted's failure to provide for Savannah and her two sons. Frustrated by Jo's interrogation and overwhelmed by the rumors spreading about her, Savannah calls Eunice and begins interrogating her about what took place between Marian and La'Roy, which prompts Eunice to insult Savannah for her struggles to meet her financial needs. As Savannah plots revenge against Eunice, Jo continues interrogating locals, and discovers from a man named Burris that Ted Temple was spotted poking around the crime scene.

Ted, for his part, is in grief over the loss of Marian, with whom he was having a secret affair. In the weeks leading up to the death of the Harmons, Ted had attempted to sell the building where Marian worked to a white supremacist named Jeff Darby, and Marian had grown angry with him for interrupting her livelihood and selling out her assets to a man who was known to hate Black people. Marian began threatening to expose their relationship to Darby in order to prevent the sale of the building, spawning a public disagreement between them that was witnessed by several people. When Jo comes to interrogate Ted, he passes the altercation off as a typical dispute between landlord and tenant, concerned that his mother, Hera, might learn about his affair and disown him as he once disowned Savannah. In the meantime, Savannah breaks her silence toward Ted in order to approach him with a plan: she intends to use Ted's pull with the police department to pin the murder of the Harmons on Eunice.

Lymp finally takes a polygraph test and is able to prove his innocence to Jo; when she calls her brother Herschel to celebrate this news, though, Herschel complains that Lymp's father, Jessie Earl, was abusive toward him as a child because he caught Herschel having a romantic affair with another boy. Eunice is arrested by the police, and a Black officer named Percival stops by Lymp's house to tell him and Jo the news, which prompts Jo to begin considering the connections between Jessie Earl's homophobia, Marian's furtive business practices, and Eunice's attempts to bring her son to conversion therapy. That night, it occurs to Jo that there are gaps in the alibi provided by Hera Temple for the night of the Harmon murders, and she calls Percival to urge him to investigate them. When the police arrive at Hera Temple's house to interrogate her, she openly confesses to the murder, explaining that she did it to protect her son after overhearing Marian threatening him; she is arrested, Eunice is released, and Ted dies of a heart attack. As the novel concludes, Eunice works to repair her relationship with La'Roy, Savannah dreams of starting over in New York City with her sons, and Jo and Lymp reconcile.