Golem and the Dragon Girl — Sonia Levitin

Laurel Wang knows that the ghost of her beloved great-grandfather lives in the oak tree outside her house. But now her grandparents are arriving from China, and the family must move to a bigger place, leaving the protective spirit behind.
Twelve-year-old Jonathan and his family are moving into Laurel's house -- and he's not too happy either. He's living with a stepfather he can't stand and a dog he didn't choose; now he has to say goodbye to his old neighborhood and his wonderful Uncle Jake.
But moving blues soon give way to angry ghosts, fortune cookies that predict the future, and a very scary accident, as the two teenagers with very different backgrounds join together to investigate a mystery and in the process discover something remarkable about each other.