Sister Monica Joan is found wandering near the docks, and returned to Nonnatus House by the police. Her adventure takes its toll on her health and she succumbs to pneumonia. When she eventually recovers, she sails forth back into the community, only to find herself in trouble with the law when she is accused of theft. As Sister Monica Joan's case progresses to trial, the Nonnatus House community fear that the old nun could find herself going to jail. Already concerned about Sister Monica Joan, Chummy has further worries when her mother decides to make a trip to inspect her new 'beau'. The visit is not a success, and Chummy suffers a crisis of confidence and breaks off her relationship with PC Noakes. Jenny and the other midwives pull together to convince her she is making a mistake.