Season synopsis
Contains spoilers for this season and earlier seasons.
As the First World War changes the household, Matthew and footman William serve at the front, Thomas joins the medical corps, and Sybil trains as a nurse. Downton becomes a convalescent home for wounded officers, bringing Isobel into a dispute with Violet and Cora. Matthew returns on leave engaged to Lavinia Swire, while Mary accepts newspaper magnate Sir Richard Carlisle’s proposal. Bates’s estranged wife Vera threatens to expose Mary’s past with Pamuk; Carlisle pays to suppress the story and announces his engagement to Mary in his newspaper.
Matthew suffers a serious spinal injury and is told he is paralysed and unlikely to father children. He breaks his engagement to Lavinia, but she stays by him. William returns with terminal injuries after shielding Matthew from an explosion, and Mrs Patmore persuades a reluctant Daisy to marry him shortly before he dies. Sybil chooses Tom; after her family reluctantly gives its blessing, they marry and move to Ireland. When Bates hears Vera is dead, he faces a murder charge; Anna secretly marries him before police arrest him, then supports him through the trial.
After the Armistice, Matthew begins to regain feeling in his legs and says he will marry Lavinia. The Spanish flu strikes Downton: Cora and Carson recover, but Lavinia dies after hearing Mary and Matthew confess their love. Although Lavinia tells Matthew she will not prevent his happiness, he blames himself for her death and tells Mary they cannot be together. At Christmas, Bates is convicted of Vera’s murder, but Murray’s appeal commutes his death sentence to life imprisonment. Mary breaks with Carlisle, tells Matthew the truth about Pamuk, and prepares to leave for America; Matthew puts the past aside and proposes.