The Enemy Within
A transporter malfunction results in two separate Capt. Kirks—one, meek and indecisive, the other, violent and animalistic. Meanwhile, a landing party is stranded on a frozen planet. In this episode, McCoy first utters the phrase “He’s dead, Jim.” Fisher: Edward Madden. Lt. Farrell: Jim Goodwin. Spock: Leonard Nimoy. Sulu: George Takei. McCoy: DeForest Kelley. Written by Richard Matheson