"Of her two granddaughters, Grandma Yvette clearly prefers Ruby Taylor's perfect--and perfectly Jewish--cousin, Sarah. They do everything together, including bake cookies and have secret sleep overs that Ruby isn't invited to. Twelve-year-old Ruby suspects Grandma Yvette doesn't think she's Jewish enough. The Jewish religion is matrilineal, which means it's passed down from mother to child, and unlike Sarah, Ruby's mother isn't Jewish. But when Sarah starts acting out--trading in her skirts and cardigans for ripped jeans and stained t-shirts, getting in trouble at school--Ruby can't help but be somewhat pleased. Then Sarah suddenly takes things too far, and Ruby is convinced Sarah is possessed by a dybbuk, an evil spirit... that Ruby may or may not have accidentally released from Grandma Yvette's basement. Ruby is determined to save her cousin, but a dybbuk can only be expelled by a "pious Jew." If Ruby isn't Jewish enough for her own grandmother, how can she possibly be Jewish enough to fight a dybbuk?"