
Checkmate is hired to protect the life of Judge Leland McIntyre, who is conducting a series of lectures concerning a trial over which he presided eight years ago resulting in him sending a man to the gas chamber. Checkmate suspects that one of the students may be connected to the case and signed up for the course to get to him. In the course of their investigation, the judge begins to question his own conduct in the trial.
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.