S1, E1: It is January 1936 and diplomat Sir Hallam and Lady Agnes Holland move into 165 Eaton Place, closely followed by his widowed mother and her wayward sister. But they also need a full serving staff, for which Lady Agnes turns to an agency run by none other than Rose Buck, who used to work at the house. But the arrival of an unwelcome guest puts a strain on relations both, upstairs and downstairs.