The spellbinding new novel from the bestselling author of The Girl of Ink & Stars, winner of the Waterstones Children's Book Prize. In an Italian city ravaged by plague, Sofia's mother carves beautiful mementos from the bones of loved ones. But one day, she doesn't return home. Did her work lead her into danger? Sofia and her little brother Ermin are sent to the convent orphanage but soon escape, led by an enigmatic new friend and their pet crow, Corvith. Together they cross the city underground, following clues in bones up to the towers of Siena, where - circled by magpies - the children find the terrible truth ...