A few old friends returned to “Downton Abbey” in Season 6, episode 4. Just an episode after Tom (Allen Leech) returned from America, Gwen (Rose Leslie) made a surprise appearance at the estate. However, she wasn’t the only unexpected arrival. Mary (Michelle Dockery) was shocked to see Henry Talbot (Matthew Goode) in her house. The guests had an unanticipated effect on the family.

Rosamund (Samantha Bond) brings a guest, Mr. Harding (Philip Battley), over for lunch. Her guest brings his wife, who turns out to be none other than the maid formerly known as Gwen Dawson. When Barrow (Robert James-Collier) sees Gwen at the door, they don’t acknowledge that they know each other. She is very excited to see Anna (Joanne Froggatt), though.

When Mary asks Gwen if they’ve met, Gwen lies and says they haven’t. She discusses why she pushed her husband to support a women’s college. She feels that she could’ve done more if she had more education.

Downton Abbey 604 recap Gwen (Rose Leslie) reminds Robert (Hugh Bonneville) of his late daughter's kindness in "Downton Abbey" Season 6, episode 4. Photo: Nick Briggs/Carnival Film & Television Limited 2015 for "Masterpiece"

Barrow doesn’t let Gwen distract everyone from her past for long. He asks her if she remembers Mr. Carson (Jim Carter), and she can’t hide the fact that she used to work at Downton. She explains that Sybil (Jessica Brown Findlay) was the one who got her out of the service industry and found a secretarial job for her. “I’ll never forget her,” Gwen says. “Her kindness changed my life.”

The other servants aren’t happy that Barrow outed Gwen. Bates (Brendan Coyle) accuses Barrow of being jealous. Robert (Hugh Bonneville) even reprimands him later. Some good does come out of it, though. They remember Sybil’s kindess, which will help them make a choice about the farm later.

Mr. Mason (Paul Copley) isn’t the only one who has to worry about unemployment, though. Barrow tells Robert that he enjoyed filling in for Carson. Robert reminds him that Carson’s kindness is one of his best qualities. He tells the younger man to remember what he learned because it’ll be helpful in the future. Though he doesn’t say Barrow is being fired, it’s quite clear that Robert is planning for him to leave soon.

The plan for the farm is more pressing right now. Tom and Robert believe that the family should take over the farm. It’s more profitable, but Cora (Elizabeth McGovern) wants to help Mr. Mason.

Daisy (Sophie McShera) is quite angry when she discovers that Mr. Mason might not get the farm. Daisy decides she must confront Cora. She storms upstairs, but the family is already discussing the property. Cora asks what Sybil would do in this situation, and everyone agrees that Mr. Mason should have the farm. When Daisy comes face to face with Cora, she discovers she has no reason to be angry. She is getting exactly what she wanted.

Violet (Maggie Smith) has a little more trouble achieving her goals. The dowager countess tries to bring in more help for her side of the hospital debate. She tells Lady Shackleton (Harriet Walter) to agree with her position at dinner at Downton. The guest brings her nephew, Henry Talbot. Mary is shocked to see her love interest from the Christmas special come back into her life.

Dinner quickly becomes a hospital debate, and Lady Shackleton isn’t much help at all. She claims that she can’t really argue when she doesn’t know the whole situation. “How can I present myself as an expert when I don’t know all the facts?” Lady Shackleton asks.

“That’s never stopped me,” the dowager countess says. Luckily, Mary distracts herself by talking to Henry. He is sure to give her his phone number before heading back to London.

Things take a scary turn later that night when Anna feels a pain in her stomach and worries that she is having another miscarriage. She has to go to Mary’s doctor in London. Mary agrees to pretend that she is the one with the medical emergency and they go off.

The next morning, the doctor reveals that Anna’s small surgery worked. He’s “cautiously optimistic” that she’ll have the baby this time.

Mary uses Anna’s surgery as an excuse to see Henry. He asks her about her work and her son, and she wonders if he’ll ever make a pass at her. He asks her if she would accept it if he did. “No, but I shall enjoy the process enormously,” she tells him.

When Anna returns to Downton, Bates says he knows she has been hiding something. He worries that it’s another miscarriage, but she tells him she has good news. Bates is overjoyed that his wife is pregnant.

The family goes down to the kitchen to celebrate the newly wed Mr. Carson and Mrs. Hughes’ (Phyllis Logan) return. The couple reveal that Mrs. Hughes will retain her name at Downton in order to avoid confusion.

But not all of the servants have good news. Sgt. Willis (Howard Ward) comes to Downton to question Baxter (Raquel Cassidy). He asks her about Peter Coyle, a man from her past. The police know Peter has been very close to many crimes of theft committed by women, but no one has ever been able to pin the crimes on him. Willis wants Baxter to testify against Peter, but the maid isn’t so sure. Baxter eventually agrees to help, and Molesey (Kevin Doyle) says Peter can’t hurt her now. The maid isn’t so sure that’s true yet.

There is unfinished business upstairs as well. Robert seems to be facing a medical issue. He has a pain in his stomach and says he can’t drink port anymore. The same pain comes again later, and Cora looks concerned. However, it doesn’t seem to be an emergency yet.

“Downton Abbey” Season 6, the final season, airs Sundays at 9 p.m. EST on PBS.