The hugely successful series starring Jenny Agutter, Pam Ferris, Helen George and Linda Bassett returns with more touching and compelling stories from the nurses and nuns of Nonnatus House. In this series Sister Monica Joan goes missing at Christmas time leaving the nuns and nurses distraught. Trixie, having battled through her issues with alcohol, finds a new purpose in her keep fit classes. And could friendship blossom into something more for vicar Tom Hereward and Barbara? Meanwhile, a string of babies born with severe and devastating deformities, casts a dark shadow over the entire team at Nonnatus House as they struggle to understand why.