In the deep South, two brothers, Vincent and Michael, lead a life shaped by their tragic past. As children, they witnessed their father take his own life after their mother abandoned them, a trauma that deeply scars their psyche. Vincent, now a priest, channels his pain into an unsettling mission: he and Michael roam the highways in a mobile confessional, offering absolution to those who seek it. However, Vincent's interpretations of sin and redemption are twisted; he believes that by killing those he deems irredeemable, he can save their souls. Michael, although conflicted, remains loyal to his brother and assists in these macabre acts of vigilantism, believing it to be a divine purpose.

Their grisly routine is disrupted when they encounter Mary Francis, a kleptomaniac drifter who becomes entangled in their lives. Mary brings chaos and unpredictability, challenging Vincent's tyrannical grip over their shared dark crusade. As the trio travels together, the lines between sinner and saint blur, leading to increasing tension and violence. Mary’s presence threatens to unravel Vincent’s delusions of righteous wrath while pushing Michael towards a breaking point. Fueled by guilt, fanaticism, and a twisted sense of duty, the brothers confront the demons of their past as their grim journey spirals towards an inevitable and grim climax.