November 1916. The family and servants are busy working to get the house ready for a concert to raise funds to equip the village hospital which is to take even more casualties from the front. New housemaid, Ethel Parks, has replaced Gwen, but her boasting does not make her popular with the others. Indeed O’Brien plays a cruel trick on Ethel in front of the family. 

Robert is being dressed by William, the second footman, while Bates is away at the funeral of his mother. Robert is now Lord Lieutenant of the county. He is anxious to be allowed to fight, which makes William feel like a coward for not enlisting. William’s widowed father has begged him not to, but he assumed that once the Conscription Bill was passed, he would be called up straight away. William’s mood is not lightened when, during the concert two women give white feathers to any young men not in uniform, which includes Branson and William. Branson just laughs at the intended insult, claiming his chauffeur’s outfit is his uniform. William’s hopes are raised when Daisy, feeling sorry for him, kisses him. William misinterprets this as a sign of love and asks a trapped Daisy to be his girl. Mrs Patmore urges her to comply. 

Feeling left out of the war effort, Robert is delighted when there is a suggestion that he is going to be given the Colonelcy of the local volunteers. Attending a regimental dinner, his hopes are dashed when he realises it is only an honorary position. 

Isobel informs Robert and Cora that Matthew is engaged and wants to bring his fiancée to Downton, she feels it is time to patch things up - Matthew is in the thick of the fighting now. Despite being disappointed that Matthew has clearly moved on from Mary, Robert agrees. Isobel runs into Sybil who is shocked at the death toll of so many young men. Isobel suggests she become an auxiliary nurse. She enrols for training in York. O’Brien reports this news back to Cora who is initially unhappy at the thought of her youngest being confronted with such terrible injuries, but comes to realise how the role could actually be good for her daughter. 

Carson is trying to compensate for having only one footman and Mrs Hughes is frightened he is working himself into an early grave. Edith has been learning to drive from Branson in the hope she will use this skill as a result of all the men being called up. 

Bates returns from London and proposes to Anna. He informs her he has already asked Robert if he would be permitted to continue in the post if he were married and has even been offered one of the cottages. Anna’s dreams have come true. 

Sybil and Branson argue over the war. Branson is not going to fight to defend the British Empire. Sybil tells him he will be imprisoned. Branson blurts out that he loves her. Sybil is not exactly astonished by his feelings. 

On learning of Matthew’s engagement, Mary tells the family that she has met Sir Richard Carlisle, the owner of scurrilous newspapers and a war profiteer. Carson is hostile to Matthew’s return because of his unkindness to Mary, but Mrs Hughes believes she brought it on herself. Nor is the butler sympathetic to Matthew’s new fiancée. 

As Matthew approaches the station the following morning to begin his journey back to the front, he finds Mary waiting for him. He is glad they are friends again. She gives him a lucky charm. Mary is still in love with him, but we are not sure the same is true of Matthew. 

Bates’s wife, Vera, arrives at Downton. Anna discovers Ethel revealing Downton’s secrets to her. Vera informs Bates she has come to refuse a divorce. Now he has inherited money from his mother, she wants him back, if not she will reveal Lady Mary’s scandal to the press. Bates knows he is beaten. He will hand in his notice at once. What he does not know is that Mrs Hughes has been listening to the whole interchange via an air vent. Robert is furious at Bates’s leaving and Anna is completely destroyed. Mrs Hughes confides in Carson all she knows about Bates’s true motives for leaving. He advises her that keeping Anna’s hopes alive will not help anyone. Robert is complaining about Bates to Carson, but the latter reveals the truth about the valet’s departure. 

Violet confesses that she asked Clarkson to write to the Army Board and tell them that Molesley and William were unfit for service. When a suggestion is made that these statements are incorrect and must be withdrawn, Molesley asks Clarkson if he finds it absolutely necessary. Clarkson understands what he is being asked to do, and assures him that he will confine his retraction to William. 

Matthew is in a dug-out in northern France, as his trench is shelled he recognises Thomas who has become traumatised by the months of fighting. The two reminisce. Thomas would love to get home and work at the hospital in Downton but Matthew doesn’t think that likely. Outside in the trench Thomas lights a match and holds it above the edge of the trench. A shot rings out. Thomas clutches his hand with a cry, as blood spouts out. As he falls, he thanks God for his deliverance…