Clare (Ruth Negga) is a light-skinned Black woman who has been living her life as a white person. Not even her racist husband John (Alexander Skarsgård) realizes she's Black. Her former high school classmate, Irene (Tessa Thompson) is also a light-skinned Black woman, and one day she decides to try and see if she can fool people by going to a White dining room and taking a seat.
Clare happens to be at the same establishment and joins her old friend. When John interrupts their reunion, he thinks Irene is also white. John, believing his views are shared by all whites, begins talking about how much he hate Black people. He tells Irene that Clare shares his beliefs, but he then remarks on how Clare has been getting darker every year that they've been together, so he's given her the nickname "Nig" as a form of endearment.
Although Irene is dismayed at Clare's choice in life, the two women rekindle their friendship. Based on the novel by Nella Larsen.