When a prominent leader of St. Paul's close-knit Hispanic community is murdered, Detective John Santana promises the widow he will bring down the killer. Despite the snow and bitter cold, the case heats up quickly-suspects are killed before they can be questioned; his alcoholic partner's trigger finger draws the attention of Internal Affairs; a sexually explicit photo of a murder victim surfaces in an unlikely place; a snow plow becomes a deadly weapon; and police brass threaten to pull Santana off the case. Hunted by an assassin out for revenge and haunted by his violent Colombian past and the younger sister he left behind, Santana's simple vow to a dead man's wife becomes an oath that could cost him his life.