"The Brain Shockers"
The Enterprise establishes orbit around the planet Pollux II to investigate the strange disappearance of several spaceships in the area recently. Mr. Spock begins a sensor sweep of the planet surface. As Kirk is about to leave the bridge, McCoy arrives. He tells the Captain that several members of the ship's crew haven't had any leave or rest for months. "But the Enterprise put into Starbase 8 for R&R just two weeks ago!" Kirk replies. "The entire crew has had its rest!" "But you're wrong, Jim!" the Doctor retorts. "When was the last time you took a leave, or Spock, or Scott, or the rest of the bridge crew?" Kirk refuses to listen to him. "I give up!" the Doctor says. "Just don't come crying to me when you start seeing Centurian space snakes in your bed!"
Meanwhile on level 7, a pretty, young blonde crew member picks herself up from the deck, confused after hitting her head during the attack. Looking around, she sees a large red door that she had never noticed before, marked "off limits." "I'd better check the room to make sure nothing was broken!" she says to herself. She opens the door, and to her horror, several terrifying, ghostlike apparitions come out of the room! On the bridge, Spock tells Kirk that there are no injuries reported from the attack. As the bridge crew continues to check the status of the ship, many more of the strange ghostlike beings float unseen about them. The apparitions vanish into the bodies of the crew members - joining with them!
"Let your mind drift back, Doctor" Spock says, "to the planet Vulcan thousands of years ago, back to a group of rational men, the men who founded the new Vulcan philosophy - a philosophy based on logic, not to shaded by petty emotions! Seeking perfection, they developed a method of removing those emotions and sealing them in bottles. Discovering that removing one's emotions also dimmed that elusive spark called 'soul', they destroyed the device, and devoted themselves to teaching us the value of logic instead. Those bottled emotions survive through the centuries, Doctor, and to honor the memory of our mentors, the Vulcan people have erected a shrine for the bottles on planet BETA IV. Those bottles were secreted in room 101, until the Enterprise could deliver them to Beta IV, but during that ray attack, something went wrong!" "The bottles are broken, Bones" Kirk finishes, "those emotions are loose somewhere on the ship!"
Kirk and Scotty lead a landing party to the surface of the planet, while Spock and Dr. McCoy attempt to discover a way to locate and bottle up the loose emotions. "But how do you start?" McCoy asks. "It's like looking for a sunspot in the Milky Way!" "Spare us the analogies, Doctor" Spock replies. "We have work to do!" When they arrive on the planet, Kirk and Scotty discover that the other members of the landing party are missing!
As the two men move through the jungle, they see no animals - only plants. "It's givin' me the willies!" Scotty says. Kirk notices movement from behind a nearby bush, and Mr. Spock and Dr. McCoy step out! "Forgive us Captain, we tried to contact you" Spock says, "but the communicators aren't working!" "So we beamed down with several others to report to you in person" McCoy continues, "but they all seem to have disappeared!" Spock tells the Captain that the escaped emotions are nowhere to be found on the Enterprise. As the group continues through the forest, a huge, gorilla-like monster attacks the party! Phasers have no effect on the beast. "I've got to get out of here!" Spock shouts. "That thing will kill us all!" Overcome with blind fear, the Vulcan runs away into the forest - leaving his companions behind. Kirk shouts after him. "Spock! Come back! Come back here! You coward!"
McCoy becomes violently angry and starts yelling insults at Spock as he flees. Kirk becomes angry as well, and tells the Doctor to "shut up" several times. Finally, he and McCoy get into a fist fight! Scotty begins laughing uncontrollably at the two men. Enraged, Kirk advances on the Engineer. Just before he can attack him, all three men suddenly feel their heads clear of the powerful emotions. "It's overwork, it has to be!" says McCoy. "All our nerves are shot, Spock's included! We just let our tempers run away with us for a few seconds! But we'll be all right now!" The three men start walking through the jungle, looking for the others again.
Meanwhile, the "missing" members of the landing party are experiencing the same mysterious emotional attacks in different locations. One crewmember clings terrified to the side of a cliff wall, while a small fluffy bunny sniffs his feet harmlessly. In another part of the jungle, two security men are fighting, while a female ensign watches, laughing hysterically.
As Spock walks alone through the jungle, his head finally clears, and he puzzles over his emotional outburst. He discovers a clearing nearby, containing a huge clear dome with machinery inside. "It appears I have discovered that small area of harnessed power, the source of the ray attack on the Enterprise!" he says to himself. "Quite correct, Mr. Spock!" replies a telepathic voice in his head. "Please, come closer to the dome! I'd prefer speaking to you face-to-face!" Spock approaches the dome, and sees a small humanoid inside, sitting in a control chair with a large mechanical device strapped to his head. The creature looks human, with the exception of his huge, bee-like eyes. "Greetings, Mr. Spock!" says the creature. "You may call me Malok!"
The dome is sealed, and Spock cannot find a way in. He asks Malok to allow him to enter. "Forgive me, Mr. Spock" Malok answers, "but no! No one has entered this enclosure for the past five thousand years! You see, I am immortal! And believe me, Spock, immortality is not at all that you'd think it is! After centuries of traveling the universe, seeing, touching, tasting, one can become very, very bored! Tired of living my own life, I struck upon the idea of living the lives of others! I constructed this jungle maze and all the other equipment, and set out to capture passing ships! Your own Enterprise crew has supplied me with the most pronounced emotional experience I've ever had, and I look forward to more!"
Laughing, Malok causes a huge, green monster to appear behind Spock. Terrified, Spock runs away. The fear becomes worse, and threatens to overcome him. Spock fights a battle within himself, attempting to overcome the emotions he is feeling. "What is wrong with me?" he asks himself. "Why is my head pounding so? What has happened to me? Why am I so afraid? Afraid? But that is not possible! Fear is an emotion! I have no emotions, I can not! I am a Vulcan! This can not be, this must not be! I am Spock! I am Vulcan! I refuse to know fear! I deny my emotions! And I shall prevail!" Spock overcomes the emotions, and with his head now clear, quickly rejoins Kirk, McCoy, and Scotty. He tells Kirk about the dome, and leads the landing party back to it.
Everyone except for Spock is quickly mesmerized by Malok's "telepathic spell." They walk toward the dome, where the other Enterprise crew members are already standing. "Welcome, my friends" says Malok, "I've been expecting you! Let the show begin!" The crewmen begin behaving like raving lunatics, as a slew of emotions are unleashed.
While Malok is totally involved in assimilating the emotions of the others, Spock sneaks around to the back of the dome, and uses his phaser to cut a hole in the side. Once inside, he re-wires the mechanism that allows Malok to receive the "emotional waves", and then quickly escapes. The machinery begins destroying itself violently, and the landing party is knocked out, as it overloads them with emotional waves.
When they recover, they see Malok wracked by every kind of emotion possible. "Malok is immortal" Spock says, "He'll spend the rest of eternity on this planet, reliving those same emotions over, and over and over again!" "There's nothing more we can do here" Kirk replies. He calls the Enterprise, and has everyone beamed back aboard the ship. Later on, Spock explains what happened to Kirk and McCoy. "You see" Spock tells them, "what the Doctor had assumed was overwork was in reality, those missing Vulcan emotions! When the bottles were broken, they sought out new vessels - us! In order to save you from Malok's spell I was forced to drain the emotions from your bodies and into his dome, where they will stay for all time!" "But what about the shrine they built on Beta IV?" asks McCoy. "Really Doctor" Spock replies, "I'm surprised at you! The Vulcans are a logical race, and what more logical tribute could possibly be paid, than to put those emotions to a useful purpose?" "Mr. Spock" McCoy answers, "sometimes you drive me mad!"