Thomas, the late Sybil's husband, is absorbed into the Crawley family and the Crawley business. Thanks to his family background in sheep farming, he's useful to Matthew in turning around the business. He turns away from his crass brother who plans to live over a car repair shop and will bring up little Sybil at Downton Abbey. He is the one who wins over the Earl to accepting Matthew's business plan.
Mr. Bates returns from prison and the Crawley family gives him and his wife Anna a cottage to fix up. Prison has made Mr. Bates compassionate, so much so that he goes the distance to save the job of his former nemesis Thomas, who is gay. This is accomplished by Mr. Bates threatening to reveal Mrs. O'Brien's secret.
Sybil partners with Granny to soften up her father to allow her to take the journalism job in London. She and the editor seem sweet on each other until she finds out that he is married. When she confronts him about that he discloses he is married to a madwoman who has been institutionalized. That situation makes it impossible for him to get a divorce.
Both Matthew and Mary try to manipulate each other about not worrying why she isn't pregnant. Then both seek out a medical doctor's advice. It turns out that she required a small operation in order to become pregnant.
Granny manipulates Ethel to leave Matthew's mother's house as the cook by arranging that she move to the town in which she could watch her son Charlie grow up. Granny got Charlie's grandmother to agree to that arrangement. Ethel is happy and Granny is thrilled to be rid of this stigma.
Although the Earl has to contend with a whole new emerging order, he has his wife's love back. He and Cora are close and it is Cora who unites him with his grandchild Sybil who has been baptized Roman Catholic.
In Shakespeare's plays this kind of unifying joy usually is a prelude for darker times. That's what we fear for the Crawley family. The coming attractions hint at coming trouble.