The 27th episode of Gene Roddenberry’s science fiction series Star Trek airs on NBC. The episode has been plagued by both script issues and an unusual but key piece of late re-casting. 
Stardate 3087.6: The Enterprise encounters brief but intense turbulence after entering orbit above an uninhabited world. Kirk leads a landing party to the surface to investigate any possible connection between the planet and the disturbance, and they find a man named Lazarus, who, though he seems healthy and normal, claims to be fighting his own equivalent from a universe of antimatter. Lazarus proves to be a threat to the Enterprise’s security, and the increasing blasts of turbulence seem to confirm Lazarus’s story that he has a powerful enemy in another dimension.
written by Don Ingalls
directed by Gerd Oswald
music by Alexander CourageCast: William Shatner (Captain James T. Kirk), Leonard Nimoy (Mr. Spock), DeForest Kelley (Dr. Leonard McCoy), James Doohan (Mr. Scott), George Takei (Lt. Sulu), Nichelle Nichols (Lt. Uhura), Robert Brown (Lazarus), Janet MacLachlan (Charlene Masters), Richard Deer (Barstow), Arch Whiting (Asst. Engineer), Christian Patrick (Transporter Chief), Eddie Paskey (Lesley)
Notes: Robert Brown had to take the role of Lazarus on very short notice; actor John Barrymore was originally contracted to play the part, but failed to show up on the shooting dates, earning a rare censure from the Screen Actors’ Guild and putting himself out of work for months. In the end, The Alternative Factor guest starred an alternative actor.
LogBook entry by Earl Green