Summertime in the East End brings with it new challenges when an outbreak of a rare disease erupts on a Poplar street. While Patsy and Dr Turner try to track down the source of the outbreak, suspicion over who the carrier could be threatens to break apart a close-knit family.

Sister Winifred is forced to reconsider her prejudices when dealing with a mother-to-be and Barbara inadvertently agrees to go to dinner with Tom – but is wracked with worry about how Trixie will react.