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.
Simon Bricker returns to talk about the painting with Cora. His his flirting though could have crossed the line. Mary is surprised by Charles Blake in London with a cunning plan.
After last week's altercation between Robert and Cora, their relationship is strained. Blake's scheming is coming to light after Mary unexpectedly pitted against her love rival. Edith receives some bad news and decides to take action. Baxter becomes embroiled in the investigation of Green's death.
Rosamund shows up at Downton following Edith's surprise departure. Rose is pleased to introduce Atticus and his parents to everyone. Anna and Bates think about a fresh start, now that that their problems seem to be behind them. Molesley is worried after Daisy becoming disillusioned with her studies. Mary and Blake seize a chance to send Gillingham a strong message.