As Series Four of Offspring begins, Nina is 12 weeks pregnant to her partner, anaesthetist Patrick Reid. Having recovered from the initial shock of her surprise pregnancy, Nina embarks on a mission to bring order to all areas of her life before the baby arrives. But her desire for a perfect pregnancy and home life are quickly disrupted by complications at work and the bedlam created by the ever expanding Proudman family. Nina and Patrick prepare for parenthood as Billie struggles to cope with Nina's pregnancy. Meanwhile, a new arrival sparks interest at the hospital.