1958 is drawing to a close as the residents of Poplar prepare for Christmas. Festivities are thrown into chaos when an unexploded bomb is discovered close to Nonnatus House. Electrical power in the immediate vicinity has been cut off as the nuns and nurses scramble out to join the crowds of evacuated residents scurrying down the pitch-black street. As the community struggles to stop Christmas being reduced to ashes, the Nonnatus House staff reaches out to those in need and keep spirits high, rekindling the spirit of the Blitz.