When a levee collapses in Hinowah, a small town in Northern California, Colter Shaw is brought on by his sister, Dorion, a disaster response specialist, to help locate a family swept away by the raging water, with mere hours to survive. But after a surprise attack along the river obstructs Colter's urgent search, the siblings are forced to consider a new reality: Is the levee at risk of failing from natural causes, or is someone sabotaging it?