On patrol, William and Matthew are trapped in enemy territory.
As Downton prepares to host a concert to boost the morale of the injured men, Cora and Isobel's conflict comes to a head over how Isobel's schedule affects Downton's servants. Cora is tired of Isobel running the house as if it were her own and Isobel doesn't think Cora appreciates how someone in a real profession has to operate. Feeling rejected, Isobel threatens to leave and Cora readily accepts the offer.
Isobel leaves for France, causing Mrs. Bird and Mr. Molesley to languish with nothing to do. When a soldier appears, asking for food, the two are inspired to open Crawley House once per week to provide food to hungry men coming back from war. Mrs. Patmore and Daisy learn of this and join the efforts, bringing food from Downton. When O'Brien spies men entering the home, she suggests to Lady Cora that there is something illicit going on, spurring Cora to investigate.
Finding them running a soup kitchen instead and confirming that the food is not coming from Downton's stores, but from food provided by the army for the convalescing men, Cora decides that she will help out today and so will O'Brien. She also decrees that food from Downton will have to be used from now on, so the army does not accuse them of misusing military resources.
Molesley offers his assistance to the overworked Mr. Carson, with an eye toward, perhaps, becoming Robert's permanent valet.
Mrs. Hughes is still repeatedly having to keep Ethel from fraternizing with the officers, particularly one Major Charles Bryant. When she finds the two of them having sex in the linen closet, she dismisses Ethel immediately without a reference.
Daisy frets when William does not return on his expected leave. Lord Grantham makes inquiries of the War Department and confirms that William and Matthew are both considered missing. Everyone worries that the men are wounded, captured or dead. Mary tries not to show her distress even as she is insistent on sticking with Sir Richard whom her father finds lacking.
Finding out that Bates is in the village, Lord Grantham approaches him about returning to his job and apologizing for the way he handled the other man's resignation. Bates explains that his wife, Vera, threatened to cause some scandal for the family, but does not provide details. He believes that he can give her enough money to get her to hold her tongue. Molesley is disappointed when he finds Bates has returned.
Violet fears that Sybil's working has broken down the boundaries in class that will be hard to re-erect after the war. She warns Mary that Sybil should think about her future prospects. When Mary spies Sybil chatting with Branson, she realizes that this is the type of relationship their grandmother finds troubling. In fact, there is reason for concern as Branson wants Sybil to come away with him. Sybil herself isn't sure what she wants at this time.
At the concert, Mary puts on her bravest face to sing with Edith accompanying her at piano, when they are interrupted by the surprise arrival of Matthew and William who reveal that they had been trapped while on patrol and made their way to safety. It's obvious to Cora that Mary and Matthew are still in love, despite his commitment to marry Miss Swire.
Meanwhile, Ethel comes to Mrs. Hughes, destitute, with nowhere to go, and pregnant by Major Bryant.