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 dozens of children. Reeling from this explosive revelation, Julia discovers two new sisters - former best friend Edie Palmer and ex-Olympic athlete Roxy Doyle. Against all odds, the three women attempt to form a bond as sisters, even as they must welcome a tidal wave of new siblings into their rapidly expanding family.