Only child Julia Bechley finds her life turned-upside down when her father reveals that, over the course of his prize-winning career as a pioneering fertility doctor, he used his own genetic material to conceive upwards of dozens of children. Reeling from this explosive revelation, Julia discovers two new sisters – former best friend Edie Palmer and ex-Olympic athlete Roxy Doyle. As these three young women begin to embrace their new reality, Julia must figure out what life is like without her father by her side; Edie comes to grips with her burgeoning sexuality, as her marriage falters; and Roxy faces adulthood out of the spotlight. Against all odds, the three women will attempt to form a bond as sisters, even as they must welcome a tidal wave of new siblings into their rapidly expanding family.