An unwelcome visitor delivers an ultimatum to Mary; Robert is considering cutting down on the number of servants at the manor.
Mr Molesley begins his career in teaching, but his first lesson does not quite go as planned; Spratt tries a new job.
A former housemaid visits; Sergeant Willis asks Baxter to testify; Thomas struggles to fill Mr Carson's shoes; a crisis takes Anna and Mary to London; Daisy has a bone to pick with Cora.
As part of her scheme to squash the plans for the hospital, Violet invites Neville Chamberlain, minister of health, to dine at Downton Abbey.
Preparations have begun for Rose's big day, but there are tensions on both sides of the family that threaten to derail proceedings.