Black bird, blue road

"Ziva will do anything to save her twin brother Pesah from his illness--even facing the Angel of Death himself. Pesah has lived with leprosy for years, and the twins have spent most of that time working on a cure. Then Pesah has a vision: The Angel of Death will come for him on Rosh Hashanah, just one month away. So Ziva takes her brother and runs away to find doctors who can cure him. But when they meet and accidentally free a half-demon boy, he suggests paying his debt by leading them to the fabled city of Luz, where no one ever dies--the one place Pesah will be safe. They just need to run faster than The Angel of Death can fly"--Provided by publisher.