The House at Riverton by Kate Morton
"Grace Bradley was just a girl when she began working as a servant at Riverton House in 1914. For years, she worked for the Hartford family and was particularly devoted to the glamorous daughters, Hannah and Emmeline. Then during a glittering evening party at the House, the body of a young poet was found. The only witnesses to his shocking suicide where Hannah and Emmeline.
Decades later, when Grace is living out her days in a nursing home, she receives a visit from a young director who is making a film about the events of that summer in 1924. She takes Grace back to Riverton and reawakens her memories of the last days of Edwardian aristocratic privilege, of the vibrant twenties and the stunning secret Grace has been keeping all her life."
It's very Downton Abbey-esque, as it covers much of the same time period. Grace is a heroine worthy of admiration by the way she takes her life into her hands and makes someone important out of herself. Her admiration of spoiled rotten Hannah and Emmeline is harder to understand. Life in early twentieth century England is interesting how world events hit both the wealthy and the servant classes similarly.
One of the two big twists at the end was easily predicted early on and possibly the second as well, except that the author kept cutting away whenever mentioning the suicide until last pages.
