Book excerpt: After Jewish fifth-grader Ava and her Muslim best friend Nadeem are called hateful names at school, Ava's Granny Buena rummages in her closet and pulls out a glittering crystal button box. It's packed with buttons that generations of Ava's Sephardic ancestors have cherished. With the help of Granny's mysterious cat Sheba, Ava and Nadeem discover that a button from the button box will take them back in time. Suddenly, they are in ancient Morocco, where Nadeem's ancestor, Prince Abdur Rahman, is running for his life. Can Ava and Nadeem help the prince escape to Spain and fulfill his destiny, creating a legendary Golden Age for Muslims, Jews and Christians?