Catriona and James are desperate for children, and embark on an IVF program. After a gruelling round of treatments, Catriona finally falls pregnant, and they donate their remaining embryo anonymously. Diana and Liam are on a waiting list to receive an embryo. Sooner than expected, they are thrilled to discover one is available. After a difficult pregnancy, Catriona gives birth to Sebastian. But severe postnatal depression affects her badly, and quickly...