April 1917. With John still absent, Isobel's butler Molesley makes a play for Anna but is rejected. Robert gets a new valet, shell-shocked ex-soldier Henry Lang, whilst William goes off to war. Edith learns to drive a tractor extremely well, and nearly succumbs to a kiss from the married farmer Mr. Drake. Sybil and Thomas work in the cottage hospital, where the latter begins to learn some humanity. At Isobel's suggestion - and to Violet's dismay - Downton Abbey is turned into a convalescent ward to ease the hospital's bed shortage. Mary invites middle-aged newspaper tycoon, and prospective beau, Sir Richard Carlisle to a dinner party, also attended by the Crawleys and Lavinia. Suspicious of Carlisle, Violet invites her daughter and sister to the Earl, Lady Rosamund, who is intrigued by the fact that Carlisle and Lavinia already seem well-acquainted. Carson, despite being taken ill whilst serving dinner, is still perceptive enough to suggest to Mary that Matthew is really the man for her.

Downton is turned into a convalescent hospital for the war wounded and through circumstances Thomas is given authority in its operation as Anna and Bates are briefly reunited and Branson plots against a heroic general dining at Downton.