Harper and her two sisters face extreme danger and unexpected natural disasters while hiking in the Cascades of Oregon. Nonstop action, survival, high school science, and sibling rivalry are the hallmarks of this contemporary realistic survival story by the acclaimed author of Black Hole Sun.

Fourteen-year-old Harper Anderson is embarking on a camping trip with her family: twelve-year-old sister Ryker, a know-it-all who likes to push her buttons; sweet, eleven-year-old sister Jentry; and their dad Jordan, who is trying his best to keep the family together. The trip is to honor their recently deceased mother, whose ashes they carry with them. Fittingly, they are hiking South Sister, one of the three volcanic peaks of the mountain range called Three Sisters in central Oregon. But when the mountain suddenly erupts, their memorial hike turns into a harrowing fight for survival. With Dad injured, it's up to Harper to get her family safely off the mountain, amid explosions, fires, glacier melt, cave-ins, acid rain, and more tests of her wits and courage.

This thrilling survival story, written with propulsive pacing and filled with breathtaking action by acclaimed author David Macinnis Gill, is also an exploration of grief, sibling rivalry, and the unbreakable bonds of family. For fans of Gary Paulsen and Mindy McGinnis.