Downton Abbey's fourth season finds Lady Mary, a widowed aristocrat, still grieving her husband Matthew. Her sister, Lady Edith, navigates a complicated romance with Michael Gregson, who disappears. The downstairs staff faces their own turmoil, particularly Anna Bates, who is assaulted by Mr. Green, a valet.

The central conflict revolves around Anna's trauma and her husband Bates's desire for revenge against Mr. Green. Edith discovers she is pregnant with Gregson's child and ultimately decides to give the baby up for adoption to a tenant farmer. A shocking twist occurs when Mr. Green is found dead, and Bates's suspicious actions lead Anna to fear he is responsible.

The season concludes with Edith secretly placing her daughter with the Drewe family. Lady Mary, aware of Bates's potential involvement in Green's death, burns evidence that could implicate him, protecting him and the family's reputation.

Season 4 of Downton Abbey covers episodes 1-8. Here's everything that happened:

Season 4, Episode 1: Episode 1 - Six months after Matthew's death, Lady Mary remains deeply in mourning. O'Brien's sudden departure brings Edna Braithwaite back to Downton. A hidden letter from Matthew is discovered, naming Mary his sole heir, sparking conflict with Robert. Encouraged by Violet, Mary begins to embrace her new responsibilities, ultimately choosing life over continued grief.

Season 4, Episode 2: Episode 2 - A house party at Downton sees Lady Mary engaging with Lord Gillingham, while Edna schemes to entrap Tom Branson. Downstairs, Lord Gillingham's valet, Mr. Green, violently assaults Anna Bates during the festivities. Anna, deeply traumatized, confides in Mrs. Hughes but insists on concealing the attack from her husband, Bates, fearing his violent retribution.

Season 4, Episode 3: Episode 3 - Anna grapples with the aftermath of her assault by Mr. Green, refusing to confide in Bates and requesting to move back into the house. Lord Gillingham proposes to Lady Mary, but she declines, still grieving Matthew. Edna Braithwaite's manipulative plot to force Tom Branson into marriage is exposed by Mrs. Hughes, leading to Edna's swift and permanent departure from Downton. Lady Edith deepens her relationship with Michael Gregson, sleeping with him before his planned trip to Germany. The episode concludes with Anna's secret remaining a heavy burden.

Season 4, Episode 4: Episode 4 - Anna struggles in silence after her assault, pushing Bates away. Mrs. Hughes eventually reveals some details to Bates, who then reconciles with Anna, assuring his unwavering love. Meanwhile, Edna tries to trick Tom Branson into marriage with a false pregnancy claim, but Mrs. Hughes exposes her lie, leading to Edna's permanent departure from Downton. Bates secretly vows revenge against Anna's attacker.

Season 4, Episode 5: Episode 5 - Edith discovers she is pregnant with Gregson's child, who remains missing in Germany. Alfred departs for cooking school, leaving Daisy heartbroken. Rose surprises Robert with a jazz band for his birthday, culminating in a scandalous kiss with singer Jack Ross witnessed by Mary. Bates learns the truth about Anna's assault. The episode concludes with Edith contemplating her uncertain future as a single, pregnant woman.

Season 4, Episode 6: Episode 6 - Edith, pregnant with Michael Gregson's child, travels to London with Rose and Rosamund, ultimately deciding against an abortion at the last minute. Mary and Charles Blake bond while saving the estate's dehydrated pigs, sparking a mutual attraction. Mrs. Hughes reveals Anna's assault to Mary, and Bates grows suspicious of Mr. Green's involvement. Violet falls ill with bronchitis, leading to Isobel nursing her and the start of a new friendship. The episode concludes with Edith returning to Downton, her secret intact, and Bates now aware of Green's villainy.

Season 4, Episode 7: Episode 7 - Lord Grantham travels to America, while Mr. Green's return deeply distresses Anna. Edith decides against an abortion, choosing to keep her baby. Rose's romance with Jack Ross ends. At the church bazaar, it is revealed that Mr. Green has died in a road accident. Bates returns from a mysterious trip, leaving Anna terrified and suspecting his involvement.

Season 4, Episode 8: Episode 8 - The Crawley family gathers in London for Rose's debutante ball, where a royal scandal involving a stolen letter from the Prince of Wales is averted by Bates's quick thinking. Edith arranges for tenant farmer Mr. Drewe to raise her illegitimate daughter incognito. Meanwhile, Mrs. Hughes discovers a train ticket suggesting Bates was in London when Mr. Green died, but Mary burns the incriminating evidence, protecting him. The staff enjoys a rare day out at the seaside.