The Night of the Cadre (S02E26)
Agent James West visits Warden Primwick, who unexpectedly releases the notorious killer Ralph Kleed. In a shocking turn, Kleed blows a whistle, prompting the warden to attack West with his cane. West manages to subdue the warden, who ultimately succumbs to the physical strain. Meanwhile, Kleed escapes, leaving behind a whistle that emits a unique pitch, audible only to dogs and wardens. During the warden's autopsy, Agent Artemus Gordon uncovers a franconium crystal embedded in the warden's brain, responsible for his aggressive behavior at the sound of the whistle. West then falls prey to the criminal mastermind Titus Trask, who plans to implant a crystal in West's brain, forcing him to target President Grant and seize control of the nation.