The "Hourglass Trilogy" is a series of young adult fantasy novels written by author Myra McEntire. The trilogy consists of three books: "Hourglass," "Timepiece," and "Infinityglass." The story revolves around time travel, exploring themes of love, sacrifice, and the consequences of altering time. The main character, Emerson Cole, discovers her ability to see ghosts and is drawn into a secret organization that manages time-related anomalies. Throughout the series, she navigates complex relationships and battles against various threats, all while trying to understand her powers and their impact on her life and the lives of those around her.