Moments before the world ends, two strangers pass each other on the San Diego boardwalk. Simon is taking a walk with his young daughter, Esther. Judith is jogging to relax before her first big job interview. When a cloud of ash descends without warning, swallowing the city behind them, Simon and Judith escape onto a nearby cruise ship and head for open water. The Yellowstone super eruption has begun, and the luxury vessel is their only hope of survival...