Robin by Frances Hodgson Burnett

In little more than two weeks Dowie descended from her train in the London station and took a hansom cab which carried her through the familiar streets to Eaton Square. She was comforted somewhat by the mere familiarity of things -- even by the grade of smoke which seemed in some way to be different from the smoke of Manchester's cotton factory chimneys -- by the order of rattle and roar and rumble, which had a homelike sound. She had not felt at home in Manchester and she had not felt quite at home with Henrietta though she had done her duty by her. Their worlds had been far apart and daily adjustment to circumstances is not easy though it may be accomplished without the betrayal of any outward sign. His lordship's summons had come soon, as he had said it would, but he had made it possible for her to leave in the little house a steady and decent woman to take her place when she gave it up.

She had made her journey from the North with an anxiously heavy heart in her breast. She was going to "take on" a responsibility which included elements previously quite unknown to her. She was going to help to hide something, to live with a strange secret trouble and while she did so must wear her accustomed, respectable and decorous manner and aspect. Whatsoever alarmed or startled her, she must not seem to be startled or alarmed. As his lordship had carried himself with his usual bearing, spoken in his high-bred calm voice and not once failed in the naturalness of his expression -- even when he had told her the whole strange plan -- so she must in any circumstances which arose and in any difficult situation wear always the aspect of a well-bred and trained servant who knew nothing which did not concern her and did nothing which ordinary domestic service did not require that she should do. She must always seem to be only Sarah Ann Dowson and never forget.