According to Memory Alpha's original in Universe Timeline, the story sequence is:
The Mark of Gideon : Spock's Brain : For the World Is Hollow and I Have Touched the Sky.
In the Remastered Episodes Chronology, the release sequence is
Bread and Circuses : Spock's Brain : Plato's Stepchildren.


A beautiful female intruder stuns the crew of the Enterprise and disappears with Spock's brain. After following the ion trail of her ship to the Sigma Draconis star system, a landing party investigates a suspect planet on a primitive cultural level but with a significant energy source. McCoy beams down with Spock's remote-controlled body and joins Kirk and Scotty.

They enter a cave that was prepared as a trap for the primitive men, the Morg, who live on the surface. An elevator takes them hundreds of meters below the surface. There they meet the intruder, Kara, again. She refuses to return the brain, which now serves as the "Controller" of her people, the Eymorg. The Eymorg themselves don't know how their technology works.

Kirk, however, has established a communication link with Spock's brain and finds the "Controller". Kara shows Kirk the "Teacher", a device that temporarily gave her the knowledge to remove Spock's brain, but she again denies any help. McCoy uses the "Teacher" and partially restores the brain; but when he begins to forget how the procedure works, Spock himself has to assist him.

Errors and Explanations

The Nitpicker's Guide for Classic Trekkers

Plot Oversights

  1. In the society on Sigma Draconis VI, men live on the surface and women live below. Supposedly it's been this way for thousands of years. Presumably the women mate with the men that they have taken as slaves and produce offspring. Do those offspring remain below with their mothers? If they do, how do the men on the surface procreate? When the children grow to a certain age, are the males banished to the icy region above? A small number could be kept as breeding stock.
  2. Why have the females deteriorated and lost the knowledge? ls it because they're females? They need a man's brain to tell them what to do? More likely they haven't needed to use the knowledge before.
  3. Alter Kirk forces Kara to don the Teacher, she takes on a new persona—one of great calm and intelligence. Then she reaches under her skirt and pulls out a phaser. Scott notes that the phaser is set to kill, and Kara replies that the Teacher gave her the knowledge to operate the device. She does not seem surprised that the phaser is set to kill. In fact, she apparently wants the phaser on “kill.” Note that Kara—from the time she pulls the weapon out of her skirt—never touches the setting. Also note that Kirk had the landing party set their phasers to stun. Therefore, when Kara confiscated the phasers, they were set on stun. Some time later, she set the phaser to kill and she did it before she received another dose of knowledge from the Teacher! lf the Teacher is her only source for knowledge about the weapon, how did she know how to change the setting? Natural instinct, perhaps?
  4. Trying to convince Kirk to allow him, to don the Teacher, McCoy says he might be able to retain some of the medical techniques and bring them to the “world.” Which world? Wouldn't McCoy say that he might bring them to the “Federation” or the "galaxy"? ' Of course, when McCoy loses the knowledge of the Teacher, the simple solution would be for another member of the landing party to submit to the device. Instead, Kirk allows the doctor to bumble along with his natural abilities. There isn't time for someone else to swap places with McCoy, who in any event is the best qualified to carry out surgical procedures.
  5. Does Spock have a flip-top head? Twice in this show he has major cranial surgery and his hair looks perfect immediately afterward. The knowledge McCoy received from the Teacher must have included a technique to minimise scaring.

Equipment Oddities

  1. While trying to decide which M-class planet to visit in search of Spock's brain, Kirk looks at the back of the bridge on two different occasions and quotes how much time he has left. lt’s like he's looking at a clock, but I don't recall ever seeing a timepiece in that location. Kirk could be reading the time from something that does not obviously resemble a timepiece that we would recognise.
  2. To make it easier to take Spock’s body along during the search for the Vulcan’s brain, McCoy and Scott rig a remote control device. With it, they march Spock’s body around like a robot. (I had a fleeting thought that Nurse Chapel might want to get her hands on that remote for an afternoon, but that's not really the main issue here.) Whenever Spock's body moves, it makes a clicking sound. Why is it making a clicking sound? Does he need a little oil in those knee joints? The clicking could be from mini servos, implanted to boost the signals from the remote control device.

Nit Central

  1. Alan Hamilton (Alan) on Sunday, June 10, 2007 - 11:10 pm: Equipment oddity: when they beam down, Kirk says "Suit temperatures to 72" and everyone reaches behind their backs like they're adjusting something. Apparently the uniforms have heaters built-in. Sulu could have used that in The Enemy Within. The self heating uniforms could have been developed specifically because of the events in The Enemy Within.


  1. See The Original Series category entry.

The Original Series Season 3
Spectre of the Gun I Elaan of Troyius I The Paradise Syndrome I The Enterprise Incident I And the Children Shall Lead I Spock's Brain I Is There in Truth No Beauty? I The Empath I The Tholian Web I For the World Is Hollow and I Have Touched the Sky I Day of the Dove I Plato's Stepchildren I Wink of an Eye I That Which Survives I Let That Be Your Last Battlefield I Whom Gods Destroy I The Mark of Gideon I The Lights of Zetar I The Cloud Minders I The Way to Eden I Requiem for Methuselah I The Savage Curtain I All Our Yesterdays I Turnabout Intruder
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