Hamilton

Maisie doesn't understand why her mother can't love her, but she knows that her life is deeply unhappy. When her stepfather George, leaves, Maisie has no protector, until she begins to escape into her own imagination. She first meets Hamilton as a lonely seven year old, but he has to remain a secret, for what would people think if she reveals her only friend is an imaginary horse?  Book 1 of series.