Christmas 1966 promises to be memorable one. The Nonnatus House team are faced with their busiest Christmas Day ever as the Maternity Home is filled with expectant moms and challenging cases.

Everyone at Nonnatus House is looking forward to traditional celebrations with all the trimmings, but nothing goes quite to plan. Sister Monica Joan is rushed to the hospital, and Trixie is incensed to receive a subscription to a Marriage Bureau as a Christmas gift. Meanwhile, a surprise reunion for Shelagh involves her in a deeply moving birth, and the Circus arrives in Poplar, bringing new friendships, new experiences, and an exciting adventure for Nurse Crane.