Dakota, 1951. Following the loss of their son, retired sheriff George Blackledge (Kevin Costner) and his wife Margaret (Diane Lane) leave their Montana ranch to find and rescue their young grandson from the clutches of a dangerous family living off the grid in the Dakotas. Headed by matriarch Blanche Weboy (Lesley Manville), they find themselves entangled with the entire Weboy clan, who are determined not to give up the boy. George and Margaret are left with no choice but to fight for their family.