Half-sisters Mona and Dee Dee have only one thing in common: their father. Growing up separately, these two virtual strangers suddenly become neighbors in the same San Francisco apartment building and experience the challenges of sisterhood for the first time.

Mona (Rachel True), a budding music executive, was raised by her single mother, Phyllis (Telma Hopkins), to be an independent woman who does things in her own free-spirited and sometimes sardonic style. By contrast, younger sister Dee Dee (Essence Atkins) is a privileged honor-roll college student who grew up in a two-parent home, but searches for her own identity out of the shadow of her overbearing mother, Big Dee Dee (Valarie Pettiford).

Now in their twenties, these two vastly contrasting women are discovering the advantages and joys that the special bond of sisterhood offers. But their relationship is not without its problems, as they often clash on everything from morals to money to men. Meanwhile Spencer (Chico Benymon), Mona's best friend, becomes the conscience of the group and helps build a bridge between the women.