After an inspiring trip to the Grand Canyon, Lauren Brown falls in love with geology - so much so that she convinces her husband, Kenny, to follow her from Philadelphia to East Texas, where she enters a male-dominated graduate program at Texas Polytechnic. Lauren thrives on the adventure geology affords her - studying undersea volcanoes, shepherding clueless undergraduates in a remote national park, and climbing canyons in Oregon to collect rock samples - but at home, things are deteriorating. After separating from her straying husband, she becomes best friends with Chris, an honourable male colleague who helps her fend off a predatory professor. When Mount St. Helens awakens, geologists from all over the world flock to Washington. Lauren is determined to be part of the action and witness an erupting volcano. The dream event of a lifetime is at hand. On a Saturday in May, she and Kenny, with whom she has reconciled, convene with Chris to stake out Mount St. Helens. The first day, the mountain remains annoyingly quiet. The next day, it erupts with catastrophic power - and irreversibly upends Lauren's life.