The new and final series of Downton continues tonight with the return of Tom and Sybbie to the house, but the peace is soon disrupted by an unexpected visit from an old friend. Baxter is faced with a dilemma after an encounter with Sergeant Willis, while Thomas struggles to fill Carson's shoes. Elsewhere, Anna goes to London with Mary to deal with a crisis, while her secrets seem likely to be exposed. Also tonight, Daisy is not happy with Cora while it looks as though Mary may have found herself an admirer.