Wedding bells are ringing on “Downton Abbey.” In Season 6, episode 3, Mr. Carson (Jim Carter) and Mrs. Hughes (Phyllis Logan) will walk down the aisle, but they haven’t agreed to all the details of their wedding. Carson appeared fine with Lady Mary (Michelle Dockery) taking over, but Mrs. Hughes wasn’t thrilled. According to the episode 3 synopsis, things will get worse before they get better.

“A wedding-dress drama takes a disastrous turn,” the synopsis teases. “The breakfast battle is settled.” Mrs. Hughes will need a wedding dress, but, given her employment as a housekeeper, expect hers to be a little more low-key than the white dress worn by Lady Rose (Lily James) last year. While attempting to find a dress, Mrs. Hughes also will be fighting for a breakfast. A morning meal after the wedding ceremony is a common fixture, but it won’t fit Lady Mary’s tastes. One of them will get their way, but will it be the bride or the lady?

Meanwhile, Lady Edith (Laura Carmichael) will be in London. “A handsome volunteer helps Edith meet a deadline,” the summary says. Unsurprisingly, Edith will have even more problems with her editor, Mr. Skinner (Paul Putner). Luckily, aid will come in the form of Bertie Pelham (Harry Hadden-Paton). Will his help be strictly professional, or will there be some sparks between him and Edith?

Back at Downton, Violet (Maggie Smith) and Isobel (Penelope Wilton) will still be at each other’s throats. “The hospital debate gets nasty,” the synopsis warns. They won’t be afraid to involve other people in the fight this week. Expect Robert (Hugh Bonneville) and Cora (Elizabeth McGovern) to get pulled even deeper into this war of wills.

According to the photographs below, the Crawley family will also welcome a special guest: Tom Branson (Allen Leech). In the photos, it looks as if Mary’s and Edith’s brother-in-law has returned from America.

“Downton Abbey” Season 6, episode 3, airs on PBS Sunday at 9 p.m. EST.

Downton 603 Mary (Michelle Dockery, left) and Edith (Laura Carmichael) will come together to watch a wedding in the final season of “Downton Abbey.” Photo: Nick Briggs/Carnival Film & Television Limited 2015 for Masterpiece Downton Isobel Isobel (Penelope Wilton) will be angered by the hospital debate in “Downton Abbey” Season 6, episode 3. Photo: Nick Briggs/Carnival Film & Television Limited 2015 for Masterpiece Downton Tom returns Mary (Michelle Dockery, left), Tom (Allen Leech) and Edith (Laura Carmichael) will reunite in “Downton Abbey” Season 6, episode 3. Photo: Nick Briggs/Carnival Film & Television Limited 2015 for Masterpiece Downton Edith Edith (Laura Carmichael) will still have trouble with her editor in “Downton Abbey” Season 6, episode 3. Photo: Nick Briggs/Carnival Film & Television Limited 2015 for Masterpiece

Downton Abbey 603 spoilers Cora (Elizabeth McGovern) will be frustrated by the fight over the hospital in “Downton Abbey” Season 6, episode 3. Photo: Nick Briggs/Carnival Film & Television Limited 2015 for Masterpiece