The following version of this book was used to create the guide: Harris, Zakiya Delila. The Other Black Girl. Atria Books, 2021.

At a New York publishing house called Wagner Books, a Black woman named Nella Rogers struggles to climb the ladder as an editorial assistant as she deals with covert racism within her workplace. At the same time that Nella finds herself in a fraught position with her own editor, Vera, another editor at the company hires a Black woman named Hazel-May McCall to work as her editorial assistant. Nella is initially excited to begin working alongside Hazel and feels relieved to have an ally at the company with her. As Nella struggles with how to communicate to Vera that a character in the new novel from Colin Franklin—one of Wagner's best-selling authors—amounts to a racist caricature, Hazel becomes increasingly friendly and conspiratorial with Nella, eventually urging her to speak out against Colin's novel. When Nella takes Hazel's advice, Colin storms out of the room, and Vera grows angry and dismissive toward Nella.

As Nella struggles to mend her relationship with her boss, she begins receiving hateful notes from an anonymous sender encouraging her to leave the company. When she reveals these developments to her best friend, Malaika, Malaika insists that the notes are racially motivated, then floats the idea that Hazel might be sending them. Though Nella rejects the idea, she begins to grow increasingly suspicious of Hazel, a feeling that only becomes more acute when she discovers a printed list of Black women's names and addresses in the Wagner copier that it seems clear Hazel has printed out. When Vera sends Hazel a manuscript without copying Nella on the email, she becomes convinced that conspiracy is afoot.

Nella's instinct is to take her concerns to Richard Wagner, the white man who owns the publishing house, but she is rebuffed from this idea when she finds Richard having a covert conversation on his phone with someone named "Kenny." Hazel and Vera grow increasingly close while Nella struggles to find time to speak with her boss. Although Nella is eventually able to reconcile with Vera, she does so at a cost; Vera forces her to apologize to Colin for accusing him of racism. When the company has a meeting about Colin's book, Needles and Pins, and Hazel speaks out in defense of the character that Nella finds offensively racist, Nella feels betrayed by Hazel.

Nella attends a reading hosted by Hazel's non-profit after work and is astonished to discover that Richard, who has long dismissed Nella's own diversity initiatives, is donating a large amount of money to her cause. When Nella confronts Hazel about her defense of Colin, Hazel writes it off as a survival mechanism and invites Nella to her house for a hair-care hangout as a peace offering. Meanwhile, elsewhere in the city, a young activist named Shani completes work for an organization called The Resistance, which has identified a number of nefarious sleeper agents they have dubbed OBGs—"Other Black Girls"—that are working to undermine the careers of Black women throughout the publishing industry. Shani begins working with Kendra Rae Phillips, a former editor at Wagner, who was fired in the 1980s after her inflammatory statements about racism nearly led to the destruction of the career of her best friend and author, Diana Gordon. As Nella becomes increasingly concerned about Hazel's acquiescence to her white bosses, Shani decides to step in against orders from her organization and contact Nella. This plan goes awry, however, when Shani is followed and kidnapped en route to their meeting place.

It becomes clear that Richard is responsible for the creation of OBGs, and that he has been working with Diana Gordon—who has developed a hair product that makes Black women more compliant—to groom them. Meanwhile, Nella and Malaika attend the hair-care gathering that Hazel has invited them to. At this gathering, Hazel manages to put some of the product in Nella's hair, and Nella manages to discover a collection of files in Hazel's bedroom that make it clear she has been targeting a number of Black women for conversion. Although Nella is alarmed, she does not take Malaika's advice and expose the situation. Instead, she goes to work the next day, where she has a meeting scheduled with a prominent Black activist, Jesse Watson, whom Wagner has invited to consult on a novel. When it becomes clear to Nella that Hazel has gotten to Jesse, she runs to the bathroom and cries. Hazel corners her there and offers her some of the hair product, which Nella accepts.