Nurse Crane is shocked when her fitness comes into question during a ventouse training course. Trixie cares for a Hindu mother and her newborn twins, but it’s not long before an emergency gastroenteritis outbreak is declared at the maternity home.

Georgiana gets a surprise visit. Colbourne’s shooting party goes ahead and Charlotte has to confront all that she’s lost. Mary and Tom cross swords over his plans for the old town.

As she sets about helping a mother whose newborn baby is suffering from a clotting disorder, Nancy is harboring a secret of her own. Sister Veronica meets a newlywed on her rounds, and the case shocks the women of Nonnatus house.

Georgiana faces a nearly impossible task in trying to find a lawyer, but help arrives from a surprising place. Lady Denham accepts a new vision for the town and spars with an old flame. Arthur makes a new friend.

Lucille struggles with her mental and emotional health; Sister Julienne is deeply concerned by an angry red rash on a patient’s breast and a referral is quickly made to St Cuthbert’s.

After confessing her true identity to an angry Johnny, Ellie unsuccessfully tries to persuade a police inspector that Frances's and Greg's deaths were linked. Drunk and abusive, Frances's husband David turns up and admits to an affair with Milena to spite his wife's infidelity. Obtaining the truth behind the murders puts Ellie into danger.

Ellie goes to Milena's workplace using a fake name under the guise of being helpful – but really looking for clues as how Milena knew Greg. Milena's business partner, Frances Shaw, confides in Ellie that her own marriage is over, as she had fallen for Milena's lover. But Ellie does not get the chance to find out the name of Frances’ lover.

When Eliza receives a bomb in the mail, she teams up with Duke, Moses and her old enemy Patrick Nash to find out who is behind the delivery.

Eliza is on the verge of earning life-changing money when she offers to help the heir to an unclaimed fortune. It’s a race against time to claim the money and Eliza will need Duke’s help, but a revelation about his personal life makes working together impossible.

Detective Fitzroy sees one of his colleagues plant evidence on a suspect. With Duke away, Fitzroy turns to Eliza for help.