
Jed and Dr. Hyatt go undercover as members of a hobo community to protect a man known as Doc, acknowledged leader of the community. Years ago Doc was disinherited by his wealthy father for behaving irresponsibly with money, but now his dying father wants him back, and others in his family want him dead so they won't have to pay him an allowance. When Doc winds up inheriting the entire estate, he goes to town with it, making Checkmate's job more difficult.
A fictional state governor running for re-election stages a phony assassination attempt to boost his chances for victory, and hires Checkmate, ostensibly for protection, but in reality to provide an appearance of credibility. The governor's son is vocal in opposing his father's tactics, but dutifully goes along, mindful of a future political career of his own. Meanwhile, as the campaign winds down, a real threat to the governor's life emerges from within his own campaign.
Luther Gage, an egomaniacal, methodical killer whom Dr. Hyatt helped send to prison, vows revenge and conducts a plot planned to the last detail to carry it out. Checkmate employs the services of Chris Devlin, seen here for the first time, to enter the prison posing as a new inmate to figure out and thwart Gage's plan.