Riley Flynn returns home to family dysfunction, familiar faces and a new priest at St. Patrick's. Elsewhere on the island, a dark storm is brewing.

An unsettling omen washes ashore in the wake of the storm. Later, when the locals gather for a potluck, tragedy strikes — and a miracle occurs.

Erin turns to Riley after receiving upsetting news. Father Paul starts experiencing disturbing side effects. Bev makes a startling discovery.

Sheriff Shabazz fields multiple missing persons reports as the town prepares to gather for Good Friday. To protect Erin, Riley brings the truth to light.

A fervent Bev calls for faith on the night of Easter vigil. Sarah reveals the results of a troubling experiment — along with a sobering hypothesis.

Night falls on Crockett Island as a tight-knit group of rebels take refuge where they can and forge a plan to control the chaos.