One moment can change everything. 1842, Mt. St. Helens in the Oregon Territory erupts, spilling its poisonous ash into the Pacific Ocean. This crucial point of divergence sets the scene for The Oregon War. The ash instead follows the wind south, obliterating any towns and farms in its path. The Harper family, caught in the middle of this new nightmare, must now brave nature as well as two superpowers vying for control of the area. All is upended when Sarah Harper meets William Taylor, and they find themselves torn between William's oath to Queen and country, and Sarah's loyalty to her countrymen.