Tragedy befalls Maine's Carrabassett Valley as Catherine Thomaston, a theoretical physics professor with a brilliant career at Bowdoin College, takes ill after the sudden death of her father. Forced into retirement by this terrible illness, she has been living a quiet life of isolation just north of Farmington, Maine. But, her illness falls into a sudden downward spiral when she is faced with her worst fear. But through its course, her best friend, Nancy, has been there to support her at every step.

Then, one night, a storm rages through, knocking power out for thousands. Now in the dark, and out of touch with the rest of the world, Catherine finds herself truly isolated and is quickly confronted by her demons. And Nancy, the only person she has ever been able to count on, has accidentally stumbled into her world of terror, rage and madness. But, her compassion has closed any doors of escape as Catherine's terrifying flight continues to rage. By the time help arrives, the final act has played itself out, leaving the people of the Carrabassett Valley with the shocking memory of an unforgetable tragedy.