Sloane, a vigilante serial killer targeting other murderers, finds herself in a dire situation, trapped in a cage with the decaying body of Albert Briscoe, a notorious killer. The stench and sight are overwhelming, testing her patience and resolve. Her predicament takes a turn with the arrival of Rowan, a charming Irishman who introduces himself as the Boston Butcher, another killer of killers. Despite the grim circumstances, a spark of connection ignites between them, setting the stage for an unusual partnership.