On a frozen Alaskan island, broke diver brothers Cole and Danny Brennan nearly die hand-diving the Bering Sea for king crab to pay for their mother's heart surgery. Their uncle Ray Kessler controls every buyer in the harbor. He breaks his promise of ten grand, offers them two, and throws in the rotten crabs "for your mother." Cole walks out, and with help from Hank, an old fishmonger who owed their late father his life, the brothers rebuild Tom Brennan's first boat. Using their father's logbook, they dive grounds no one else dares to work. Ray hits back with sabotage, a fake contamination scare, cut safety lines and a fuel blockade. Cole is calm and always one move ahead, and every attack ends with Ray humiliated in front of the whole harbor. Then Marisol Vargas pulls up in a red Lamborghini as the West Coast's biggest live-crab buyer, and the town starts changing sides. But a sea monster haunts the deep, and an old mapmaker is hiding a secret about the "calm water" that sent their father to his death.
