An unprecedented oil strike in Willistown, North Dakota leaves the town a focal point for trouble. Law and order is a dim memory and the sheriff's department just can't build the jails fast enough. Investigator Cassie Dewell is thrust into the middle of a gang war in the crime series that inspired Big Sky.Can one woman tame them? 30º below zero, but Grimstad – like hell – hasn't frozen over. The town in the middle-of-nowhere has struck oil. As oil flows out, men and money flow in. With them comes organized crime. Cassie Dewell, Grimstad's newly appointed deputy sheriff, has been thrust into the middle of a brutal gang war that's leaving bodies scattered across town. Cassie knows she's in over her head. But one witness keeps turning up at her crime scenes: a 12-year-old boy with a habit of being in the wrong place at the wrong time. And he might just be the key to her survival.