The House on Pendleton Block — Ann Waldron

When the Ransoms pick up and move from Georgia to Texas, twelve-year-old Chrissie has grave misgivings about her new home. Lonely and left on her own, she spends most of her time exploring the once-fashionable mansion her family has rented. Hamilton House intrigues her: Its secret passageways, the attic crammed with antiques and memories, and especially its former owner, the late Alberta Hamilton, who had a lot of secrets. With the help of her new friend Camilla, Chrissie finally ties up the loose ends of Alberta's life and unravels the intrigues of Hamilton House.