A Labour government comes to power in the general election; Lady Mary receives another proposal from Tony Gillingham.
It's the summer season and as part of Rose's `coming out' she is to be presented at Buckingham Palace. The family and servants are at Grantham House, their London residence, preparing for the busy social season.
Rosamund comes up with a plan to help Edith deal with her problem, but Violet may be about to see right through it; Isobel is the object of someone's attention; Mary asks Gillingham for a favour.
There's trouble when Mary takes Marigold to the farm and they are spotted by Mrs Drewe; Carson and Mrs Hughes have different ideas about their wedding; Edith argues with the magazine's publisher; Anna sees a doctor.
An exciting opportunity creates tension between Ivy and Daisy; Isobel attempts to appeal to Violet's charitable nature, but it does not come without a struggle; Branson considers a new future for himself and baby Sybbie.