It's December 1966, and good tidings are in the air. Following a long engagement, Lucille and Cyril are excited about their upcoming nuptials and can't wait to get married on Boxing Day. However, as the day approaches, nothing seems to run smoothly, and the wedding ceremony itself is put in jeopardy.While Nancy focuses on her final midwifery examinations, it is all hands on deck as the Nonnatus team prepare for what will inevitably be a busy Christmas. The maternity home is filled with expectant mums-to-be, each with their own challenging case.