Returned to their penitentiary by Lucky Luke for the umpteenth time, the Daltons meet a troubling character: Dunkle, a self-proclaimed prophet fond of fiery speeches. His continual preaching eventually converts the ever hapless Averell. Soon, all five escape together and find refuge in a friendly, welcoming community, where they sow chaos and discord each in their own way - unaware that Lucky Luke is already tracking them...