Local plans for a war memorial see Carson pitted against Robert and Mrs Hughes. Jimmy receives some female attention that causes him major problems. Baxter is issued with an ultimatum. Tom's burgeoning friendship with Sarah Dunning causes Robert concern. Mary feels ready to try and find love again. Edith and Drewe’s special arrangement starts to crumble as she increasingly finds it hard to keep her emotions in check resulting in some disastrous consequences for everyone.
Robert is left with a difficult decision to make. Mrs Patmore has an idea which might solve everything as Daisy continues to struggle with her studies. Thomas has issues with Baxter, however will his meddling ruin her friendship with Molesley? Rose tries to convince Robert of the positives of a wireless at Downton. Lord Merton continues to pursue Isobel while Mary puts her reputation in danger when Anna is made an accomplice.
Robert is left furious when things don't go as planned. Mary's undercover assignment is nearly blown. Violet is quick to save the day. The events surrounding Green's death are under scrutiny. Mrs Patmore is left devastated when old wounds are opened. Branson receives a proposition regarding the future of the Downton estate.
Sarah continues to cause trouble above stairs, however this time she may have gone too far. Elsewhere Thomas is suffering an illness, Baxter suspects there is more to it than he is letting on. Violet reveals the truth to Isobel the truth about her past with Prince Kuragin. Mary comes to a decision regarding Lord Gillingham.