Set in April 1917 and with many of the male staff serving in the war, Carson finds himself under pressure to make sure that duties are carried out to his exacting standard. He ends up finding himself forced to accept female staff serving in the dining room. Robert needs to hire a new valet and ends up employing Lang, who has just returned from the war. William is happy after he receives an important letter. Mrs Patmore finds out some devastating news about her soldier nephew. Thomas returns from the war and begins work alongside Lady Sybil in the local hospital. After a patient is brought in suffering with gas blindness Thomas finds himself becoming attached to the young Lieutenant. Molesley takes an interest in Anna. Matthew learns of his temporary transfer back to England for a recruitment drive in the north whilst fighting in the trenches. Carson advises Mary that if she still loves Matthew she needs to tell him before it is too late.  Meanwhile Lavinia is reunited with an unwelcome face from her past.