An Amazon Breakthrough Novel Award winner--Grand Prize and Young Adult Fiction. When Kate Pierce-Keller's grandmother gives her a strange blue medallion and speaks of time travel, sixteen-year-old Kate assumes the old woman is delusional. But it all becomes horrifyingly real when a murder in the past destroys the foundation of Kate's present-day life. Suddenly, that medallion is the only thing protecting Kate from blinking out of existence. Kate learns...