Deep and Dark and Dangerous by Mary Downing Hahn is a great intermediate read. Ali has been invited to spend the summer with her 4 year cousin Emma and her Aunt Dulcie at the family cottage on the coast of Maine. Ali’s mother Claire, a depressed woman who is prone to migraines is unenthusiastic about her going. Ali’s more positive father decides finally that Ali, at thirteen, needs to get out and get some new experiences. What begins as a enjoyable journey for the three, swiftly alters when a young girl named Sissy appears and gains control over four year old, friendless, Emma. As amusing and thrilling as she is to be with, Sissy turns nasty and malicious. Ali tries her best to protect Emma, but no one will listen. As the story unfurls we learn that the strange Sissy is the key to a past tragedy at the Maine cottage.