Boxing Day brings a large snowfall that covers the country. The adverse weather causes major disruption across Poplar as roads become blocked and pipes freeze. The milk float struggles to make its deliveries and families must queue outside for water from standpipes. Trixie's holiday with Christopher is cancelled due to the snow. Valerie helps Linda and Selwyn, an unmarried couple living in a caravan, prepare for their baby. As the labour progresses, unforeseen complications knock Valerie's confidence in her ability as a midwife.