Jessamy Harrison is eight years old at the start of this book, living in England, struggling with constant nightmares, fits of fever or other illness and nameless sense of fear that causes her to fall down screaming. Her mother takes Jess and her father to Nigeria, for their first visit to her family and the house where she grew up. Jess is delighted with her Nigerian grandfather, but even more intrigued by a ragged girl, Tilly, who seems to be living in an abandoned outbuilding. Tilly can do astonishing things- open locked doors, turn invisible, steal things, and possibly place curses on people who upset her. Jess is sad to say goodbye to her new friend when she returns home but Tilly turns up at her door in England. For a while, Tilly seems like Jess's best friend. But Tilly is bitter and her vengeance is harsh. Soon, this girl who seemed like a gift begins to haunt Jess and plague her worst nighttime terrors.

This was Helen Oyeyemi's first novel, finished when she was only 19, and it shows some first novel weaknesses. I finished the book, and was very interested by some parts, but I feel like Oyeyemi explored many of the same themes (haunted twins, a blurring of reality into madness, cross-cultural clashes of beliefs) with more richness and maturity in her later novel White is for Witching. I'd recommend that one, or her brilliant short story collection What Is Not Yours Is Not Yours over this one.