Tom explains to the Crawleys his reasoning in coming back to Downton. The family discusses who will be the estate agent -- Tom or Mary. They discuss that Aunt Rosamund will be coming to town and will likely be an ally to Isobel and Cora in the hospital fight against Violet.
Mrs. Patmore informs the other servants that Sergeant Willis will be coming around to speak with Baxter. They wonder what he is coming by to speak to her about.
Cora complains to Baxter about Violet inviting over a friend, Lady Shackleton, to dinner that night to act as her "ally" against Rosamund, Cora, and Isobel. Baxter is clearly distracted and only half-listening.
Mary and Tom discuss whether they are going to be co-agents. Tom explains that he is not a traditionalist, and talks about his experience with capitalism in America. He wants to have something to do that isn't all about the estate.
Sergeant Willis arrives and questions Baxter with Mr. Molesley in the room at Baxter's request. He questions her about Peter Boyle, who was in custody for theft. Boyle is a man that has repeatedly been close to thefts perpetuated by vulnerable young women, always profitting from the crime. Willis asks Baxter to consider serving as a character witness against Boyle, to finally put him away. After Willis leaves, Molesley encourages Baxter to do it, though she says it isn't that easy.
Cora reports back to Robert that Lady Shackleton has asked to bring her nephew Henry who is in town to dinner. Tom joins them and mentions that Mary has decided to give one of the vacant cottages to Mr. and Mrs. Carson. Cora tries to suggest renting out Yew Tree Farm after the Drewes' departure. Robert is glad that Tom is back at Downton.
Mary and Anna discuss her pregnancy and how she is "thickening up" but still keeping it from Mr. Bates until the pregnancy is safe.
Violet and Lady Shackleton discuss Shackleton's nephew who is in town. Violet instructs her friend about the plan for dinner that evening: to dissuade Lady Grantham from supporting changes that will take power away from those at Downton at the hospital. Violet's friend is confused about why it would be a bad thing, if it means more modern technology, but Violet hastily shoots her down and dismisses the discussion.
Thomas, who is acting as butler, instructs everyone that they need volunteers to clean out the Cobbs' cottage for the Carsons to move into. Andy volunteers. Daisy mentions Mr. Mason moving into Yew Tree Farm and Thomas shoots it down, saying he overheard that the Crawleys will be farming the land themselves, though they may rent the cottage itself. Daisy is distraught and in disbelief, insisting that Cora implied Mr. Mason would get the farm. She rushes off.
Rosamund and Edith discuss the hospital quarrel. Rosamund explains that she's a trustee at a local college for women of modest means. She reveals that she's suggested Edith to be a trustee as well. She is in town partly to discuss it with the treasurer, Harding, who is closer to Edith's age than Rosamund's.
Molesley talks to Cora about Mrs. Baxter.
Daisy angrily mashes potatoes. Daisy claims that the Crawleys did wrong by getting Mr. Mason's hopes up. Mrs. Patmore explains that Daisy was really the one to get his hopes up and they get into an argument about it.
Lady Shackleton arrives with her nephew, Henry Talbot. Mary is surprised to see that the nephew is Henry, who she'd met the previous year. Mary and Tom talk to Henry about his car racing. Violet and Lady Shackleton discuss Henry's prospects and though Robert laughs at them, the two women agree that Mary needs more than Henry can offer.
Baxter is angry at Molesley for taking her situation to Cora. Anna enters the room and seems to be in pain. Molesley is concerned but Anna dismisses him and says it's fine, rushing off.
At dinner, Isobel and Violet face off and argue about the hospital. She calls upon her friend Prudence to back her up. Prudence declines involving herself, citing that she isn't an expert. Edith talks to Tom about his ideas for what he'll do. Tom thinks that he might do something to do with car racing. Edith points out that that would be a career that is far from Downton. Mary and Henry discuss whether he makes money from car racing.
After dinner, Henry gives Mary his card and asks her to telephone if she's ever up in London. The family discuss how to resolve the hospital dispute without all getting kicked off the board for the fuss that is being made.
Lady Shackleton and Henry depart. Robert experiences his stomach pain again.
Thomas and Baxter have an existential discussion. Thomas tells Baxter that he is jealous of her life -- that people like her and Mr. Molesley has feelings for her. Baxter says she is jealous of Thomas not minding what people say. Thomas tells Baxter she is stronger than she thinks and that she is wrong -- he does mind what people say. He walks off.
Baxter meets with Sergeant Willis. She tries to refuse testifying against Coyle, though Willis and Molesley argue against her. Willis informs her that Coyle has ruined many girls' lives -- two are prostitutes and at least one is dead. After Willis leaves, Baxter explains that she changed her mind after hearing about the girls who Coyle ruined and being reminded about how he ruined her.
Mr. Harding, the college treasurer, arrives with his wife -- who is Gwen, the old servant. Anna recognizes Gwen and greats her warmly. Mr. Harding and Gwen meet with the Crawleys. Mary recognizes Gwen's face, but Gwen says that she hasn't met her exactly.
The servants discuss Gwen's return. Daisy is a little bitter that she is upstairs, while the rest of them have remained downstairs.
Isobel quizzes Gwen about her story. Gwen explains that she was a secretary before she was married and mentions that she feels she could have gone further with more of an education. Isobel echoes the sentiment for herself. As the group exits to eat lunch, Tom moves to greet Gwen warmly, having recognized her, as Mary looks on suspiciously.
The servants wonder if Gwen will come downstairs to greet them. Thomas snidely claims that she won't because she's "too important" now to be among them.
Over lunch, Gwen espouses her feeling that society can't waste working girls' potentials by refusing to educate them. Thomas makes a comment revealing that Gwen used to be a housemaid at the house. Gwen is made uncomfortable but explains that she worked there. Everyone is confused as to why she didn't say anything.
The servants discuss that Thomas ruined Gwen's lunch. Bates accuses Thomas of being jealous. Thomas brings up that he dedicated his life to service and is now being tossed out on his ear.
The family is thrilled to hear about Gwen's success story. Gwen explains that her success was all thanks to Sybil and she explains that Sybil's kindness changed her life. The family is all tremendously moved to hear it.
Gwen and Mr. Harding come downstairs to catch up with the servants. While Gwen is catching up with Mrs. Patmore and Anna, Daisy corners Tom and tries to convince him to put in a good word for Mr. Mason.
Robert chastises Thomas for trying to catch Gwen out by rudely revealing her secret.
Mary talks to Anna about how Gwen reminded her of Sybil's kindness and how much better Sybil was than her. Anna is suddenly overcome with pain and panics, convinced that she is losing the baby. Mary snaps into action and decides they will drive into York immediately and get the late train out of York to London. She tells Anna to tell Bates that it is Mary who has the medical emergency.
Mary confides in Tom, who offers to drive them to York. She tells her family that she is going off for a medical issue. Though they are confused and worried, she assures them that she isn't in any danger and rushes off, after securing Aunt Rosamund's permission to stay in her home there. Though Bates is suspicious, he sees Anna and Mary off.
Daisy insists to the servants that Lady Grantham cheated Mr. Mason out of the farm. The others try to warn Daisy not to, but Daisy is firm that she'll wait to corner Cora alone.
The Crawleys discuss Mary's emergency. Cora tells everyone about the plan for Mr. Mason to have Yew Tree Farm. Everyone agrees.
Everyone tries to convince Daisy not to confront Cora, telling her she'll get fired and not have a reference.
Tom gets back home, and the family tells him about Cora's idea to give the farm to Mr. Mason. Robert explains that though it isn't a proper business decision, Cora used emotional means to get everyone to understand. Tom agrees.
As Robert and Cora exit the room, they're confronted by Daisy and Mrs. Baxter. Cora is hesitant to see Daisy there. Robert explains to Daisy that Mr. Mason has the farm if he still wants it. Daisy and Mrs. Baxter are both shocked and rush off. Cora comments that she seems to have dodged a bullet. Robert grimaces in pain again.
In London, Mary sits anxiously waiting for news from the doctor. The doctor joins her and tells her that the operation was successful and that he is cautiously optimistic, to her enormous relief. He instructs them to stay a few days.
Robert and Barrow discuss Carson's imminent return. Barrow mentions that he's enjoyed being the butler in Carson's absence. Robert explains that he hopes Barrow has learned the importance of kindness, as Carson is kind, and that is why people are loyal to him. He insinuates that lesson will be useful after Barrow's eventual departure as well.
Mary goes to meet up with Henry Talbot while she is in London, going out to dinner. Henry questions Mary about her passions. She explains that she likes being the agent to her estate. She is determined that Downton will not go down as many other estates have.
Mr. Mason and Daisy go to visit Yew Tree Farm and Mr. Mason is ecstatic. He thanks Daisy for using her credit to rescue him.
Bates talks to Anna about why she left for London in a rush. She confesses the pregnancy and they are both overjoyed. The servants welcome the Carsons back to Downton with a small party downstairs.
Violet joins Isobel, Cora, and Rosamund at Downton and accuses them of plotting. Violet claims that she is against government influence becoming all powerful and diminishing individuals' freedoms. Tom explains that he told Mary about Mr. Mason taking over the Drewes' farm and that while she was annoyed she didn't refuse.
The Crawleys go downstairs to join the party for the Carson. Violet, Isobel, and Branson talk to Edith about her plans for the magazine. She explains that she wants to be a co-editor and find a woman co-editor to work with. Violet is shocked by that idea but Mary praises it. Rosamund encourages Mary praising Edith.
Carson requests that he and his wife still be referred to as Carson and Mrs. Hughes. The family and all of the servants are releved to hear it.
Thomas stands off to the side, watching the festivities by himself.
Mr. Carson goes to visit his old room and sadly looks over everything, taking his name off the door, and bidding it farewell.