When Sully opposes the construction of a nearby dam, he finds himself on the other side of the law and behind bars. Sully joins forces with Preston to try and peacefully stop the dam construction which will mean the end of hundreds of acres of countryside. But when Sully hears that the men Preston's hired to hijack a shipment of dynamite are determined to kill any witnesses, Sully rides with them in order to prevent the murders. However, when witnesses attest to the fact that Sully was riding with the hijackers, Matthew is forced to arrest him and Sully must go to court where Judge Webster finds him guilty and throws him in jail, creating discord in the family.