In the First section of the book, "Negritude for Beginners" Birdie describes her life living with her sister Cole and her parents in Boston. Both parents are involved in the Black Power movement. Dad is an academic, while mom is working in more informal channels. The breakup of Birdie's family along "racial" lines occurs as the Black Power movement seemingly becomes a more dangerous activity and as it becomes clear that a white wife and daughter are a liability for someone espousing Black Power philosophy. Mom also believes that the authorities are after her for her "revolutionary" activities. After the breakup of their parents, Birdie is taken by her mom and Cole is taken by her dad.
The next third of the book covers the period that Birdie spends with her mother living itinerantly in motels and communes. To protect her daughter and herself from the expected reaction to miscegenation in rural New England (and of course the Authorities), mom renames them both, coaching Birdie with the history of her father being a Jewish intellectual who has passed away. They settle in New Hampshire where Birdie attempts to fit into the white society. Being part black, without anyone knowing it, she finds the casual racism of those around her alienating. When her mother takes up with a local man who typifies the racist bumpkin, Birdie runs back to Boston.
By revisiting people who knew her family she hopes to figure out where her father and Cole have gone. Supposedly they had fled to Brazil to escape the authorities. Her efforts do pan out and she finds out her father was living in Oakland. So, visiting her estranged (and conveniently wealthy) maternal grandmother she gets money to buy a ticket for Oakland.
Reunited with her father and Cole Birdie realizes that her mother's fear of the FBI might have more to do with a persecution complex than reality. Hoping to come to terms with why and how her father abandoned her after promising to find her when it was safe, she realizes that his academic theories of race are separate from how he is able to function in the world. Though race does not exist he had chosen to divide his daughters according to where they fit into racial categories. Cole was equally disappointing in her explanation for why they had not sought out Birdie. Cole only wanted to know why her mother had not tried to find her. Birdie realizes, in the end, that the family members she had been separated from could not answer the questions she had about why she had not been wanted.
This is an excellent novel about coming to terms with family, race, and identity. It is sad that racial categories are so important as recently as 1975, but humans are fond of categorizing the world, including themselves.