“Little Fires Everywhere,” based on Celeste Ng’s 2017 novel, is a slowly warming powder keg of an eight-part series that examines motherhood in racially torn America. Set in a self-righteous white suburb of Cleveland, Ohio, in the late Nineties, it pits two fiery women and their families against each other (although at first they join as allies): an “appearances are everything” bossy, workaholic white mother (played with steely precision by Reece Witherspoon) and a nomadic black artist (I was at first less convinced by Kerry Washington but her performance accelerated after the first couple of episodes). Four white teenage children, running the gamut from a seemingly perfect achiever who aspires to Harvard, through two very different boys, to the youngest and most rebellious, connect in complex spirals with one black teenage daughter. All five teenagers are more than ably portrayed by a fine cast. The plotline permutes the five (and the two main women and a husband, plus an illegal immigrant who abandoned her child to be adopted by another white woman) into a tapestry illustrating (occasionally with a heavier hand) themes such as racism, biracial sexuality, abortion, transracial adoption, and family secrecy. The final two episodes explode with passion and tension, and the climax works on a number of levels. Little Fires Everywhere is a splendid, tight family drama series.