Birdie and Cole are the daughters of a black father and a white mother, intellectuals and activists in the civil rights movement in Boston in the 1970s. The sisters are so close that they have created a private language, yet to the outside world they can't be sisters: while Cole looks like her father's daughter, Birdie appears to be white. For Birdie, Cole is the mirror in which she can see her own blackness.

Then their parents marriage falls apart. Their father moves in with his black girlfriend, who won't even look at Birdie, and their mother seems to be more and more out of control, giving her life over to the movement. At night the sisters watch mysterious men arrive at their house with bundles shaped like rifles.

One night, through the attic windows Birdie watches her father and his girlfriend drive away with Cole - they have gone to Brazil, she will later learn, where her father hopes for a racial equality he will never have in the States. And the next morning, in the belief that the Feds are after them, Birdie and her mother have left everything behind: their house and possessions, their friends, and - most disturbing of all - their identity.

Passing as the daughter and wife of a deceased Jewish professor, Birdie and her mother drive through the Northeast, eventually making their home in New Hampshire. Desperate to find her sister, yet afraid of betraying her mother and herself to some unknown danger, Birdie must learn to navigate the white world and the pains of adolescence - until she is finally prepared to set off in search of her sister.