The Nonnatus team rallies to support first-time parents Marie and Tony Amos when Tony is arrested for gross indecency with another male. Elsewhere, as Poplar is gripped by an outbreak of dysentery, Trixie undertakes her first official church duty since her engagement to Tom.

Sister Julienne's faith is challenged when a mother refuses medicine for her newborn baby. Dr Turner's involvement in the case forces him to face his own demons. Meanwhile, Barbara must work out a way to communicate with a pregnant Sylheti woman.