Plot Overview: Series Three
Runs through the middle part of 1920. Despite Matthew and Mary's marriage finally taking place the outlook for Downton is grim as Lord Grantham has lost most of Cora's money in failed share dealings. Eventually the estate is saved by Matthew receiving an inheritance from the father of his late fiancée, and Matthew becomes joint owner of the estate.
Edith is supposed to marry Lord Strallen, but he leaves her at the altar, saying she should not throw her life away on an old man. She resigns herself to spinsterhood and begins writing journalism, focusing on women's issues.
Sybil and Branson return from Ireland after Branson becomes wanted for republican activity. Lord Grantham manages to save Branson from arrest but only on condition he never returns to Ireland. Sybil has a healthy baby girl but shortly afterwards dies herself due to medical errors. Initially Branson is determined to break away from the family but ultimately becomes estate manager.
Below stairs the main intrigue concerns Thomas, who is tricked by O'Brien into making advances to a new footman. This very nearly leads to disaster for him, but everything turns around and Lord Grantham promotes him to under-butler. Bates is finally cleared of murdering his late wife and returns to Downton as Lord Grantham's valet.