Plot Summary for Nobody Knows: Mattie’s family are sharecroppers in the American South. When Mattie is six, Mama takes her to town where she sees two doors marked “White Only” and “Colored Only.” Mattie thinks the shopkeeper doesn’t like them. Her mother tells her at least she’s not a slave, as she was as a child. At 18, Mattie marries Nate Charles. In 1917 their cotton crop is failing, so Nate takes a job in a Chicago meatpacking plant. Mattie is sad to leave home, but she moves with her husband to work for a better life. In the North they find racial prejudice, labor unrest, and violence. They work hard, and with two children they move to a better home. Then there is an accident at the plant. Nate is killed. Alone after Nate dies, Mattie brings Mama north to help her. Through the Great Depression and World War II, she works many jobs to support her family. When Mama dies, Mattie takes her home. She finds the South still segregated. She stands up for change.