The Worldwalker Trilogy is a fantasy series written by Josephine Angelini. It consists of three books: *Trial by Fire*, *Firewalker*, and *Shadowwalker*. The story follows Lily Proctor, a teenage girl who discovers her ability to travel between parallel worlds, each with its own unique magic and dangers. As Lily navigates these worlds, she encounters different versions of herself and faces challenges that test her strength and resolve. The trilogy explores themes of identity, friendship, and the consequences of power, making it a compelling read for fans of young adult fantasy.