Real World article
(written from a Production point of view)

The Deneva colony is attacked by flying parasites that cause mass insanity while the crew of Enterprise search for a way to stop them. (Season finale)

Summary Edit


Denevan neural parasite

Flying parasites infest Deneva

The USS Enterprise approaches Deneva. Captain Kirk is concerned; Uhura has been unable to contact any transmitter on the planet, including a private transmitter code Kirk suggests. Spock's research has revealed that a pattern of mass insanity has been spreading in a straight line through this part of the galaxy, starting with Levinius V, then Theta Cygni XII, Ingraham B, and now Deneva is next, a planet on which Kirk's brother Sam is stationed with his family.

Lieutenant Sulu picks up a ship on sensors. The small craft of Denevan configuration is on course directly for the Denevan sun, and does not appear to be out of control. Kirk orders Sulu engage the Enterprise at warp 8 interception course. The Denevan vessel is out of range of the tractor beam; the Enterprise pursues. Finally, they make contact: seconds before the ship burns up, the pilot cries out "I did it! It's finally gone! I'm free!!". After the vessel's destruction, Doctor McCoy walks up to Kirk and softly asks, "Jim, your brother Sam and his family – aren't they stationed on this planet?"

Act OneEdit

Spock and Montgomery Scott inform Kirk about Deneva's history and the fact that there has not been contact in a year. Uhura reports activity on the private transmitter channel, a woman speaking but does not respond to Kirk. He identifies her as his brother's wife to McCoy.

Once the Enterprise arrives at Deneva, Kirk forms a landing party consisting of him, Spock, McCoy, Scott, Yeoman Zahra, and Bobby. Spock says there are the expected number of Human life signs, but "strangely quiet." They beam directly into the capital city on Deneva. Once on the planet, they are struck by the curious lack of people; in a city of 100,000 people, no one is visible – until, a few minutes later, they are about to be attacked by four men who, even as they charge, scream "Go away! We don't want to hurt you!" But, with their clubs, they start to try anyway, forcing the landing party to stun them with their phasers, an attitude inconsistent with their actions. Then McCoy discovers with his medical tricorder that the nervous systems of the unconscious men are violently active – as if they are somehow still being stimulated.

A loud scream draws them next to Kirk's brother's lab. Kirk's brother, Sam, lies dead on the floor. Aurelan, Sam's wife, is hysterical, and their child Peter is unconscious nearby. Evidence suggests something has been trying to force its way in, despite the fact that the sensors showed nothing on Deneva that didn't belong there.

In sickbay aboard the Enterprise, Aurelan, in terrible pain, tells Kirk that "things" came, eight months prior, on a ship from Ingraham B. As she tries to answer Kirk's questions, she experiences more and more pain, until McCoy is forced to sedate her. The creatures use the Denevans as their arms and legs, and are forcing them to build ships. They control their hosts with pain. Aurelan's last act is to implore Kirk not to let the things go any further; this effort costs her everything she has left, and she dies.

Kirk rejoins the landing party; he knows there is some sort of creature present, but the landing party has not yet discovered anything beyond a curious buzzing. Entering a building where they heard this sound, the landing party discovers strange creatures. Looking like little more than loathsome blobs of jelly, they emit an unwholesome buzzing, and employ a crude, wingless flight. A phaser at force 3, on the kill setting – sufficient to destroy most organisms – barely affects these creatures, even after several seconds of exposure. And the creatures do not even register on Spock's tricorder.

Kirk holding Spock on Deneva

"Spock, are you all right?!"

Thinking it may be a trap, Kirk orders the landing party out of the infested area; as they leave, a creature strikes Spock in the back, leaving a strange puncture wound. Kirk rips it off of Spock's back and asks the Vulcan if he is all right. Spock looks upward in pain.

In the alternate reality IDW comic, the creature attaches itself to Spock's face instead.

Act TwoEdit

McCoy removes a small strand of tissue, and then, over Nurse Chapel's objections, he closes the wound. The creatures attack by stinging; they leave behind a piece of this tissue that rapidly infiltrates the victim's entire nervous system, far too completely for conventional surgery to remove it. McCoy explains this to Kirk on the bridge while showing him the piece of tissue in a container.

Spock recovers consciousness, rages out of sickbay and storms the bridge. His goal: to take the ship out of orbit. Spock is ultimately overcome, sedated by McCoy after being held down by Scott, Sulu, and Kirk, and he is returned to sickbay, where McCoy makes another grim discovery. The K3 indicator, a measure of pain, is very, very high. The reason for the madness is confirmed: victims are in such agony that their minds eventually break under the stress. Spock, recovering consciousness, now claims the ability to control the pain. But after his visit to the bridge, Kirk isn't sure and has him continued to be confined to sickbay.

Spock, conquering the pain, breaks out of sickbay and plans to visit the planet's surface. Scotty, acting on Kirk's orders, refuses to transport him. A scuffle breaks out, including Spock using the Vulcan nerve pinch on Leslie. Scott holds Spock by threatening to stun him with a phaser and calls for Kirk to come down. Later, when Kirk appears, Spock explains that his plan is to retrieve a creature for study. He believes that since his nervous system is already infiltrated, there is little more the creatures can do to him. Kirk is convinced, and over McCoy's objections, Spock beams down to collect a creature for study.

Act ThreeEdit

Spock is attacked by a colonist on Deneva almost immediately after being beamed down. The man knocks Spock's phaser out of his hand with his club. Spock is able to incapacitate the crazed man with a Vulcan nerve pinch and, upon regaining his phaser, begins to struggle against the pain of the parasite. Spock returns with a creature he fires his phaser at and begins to study it. Immediately, in one of the Enterprise's science labs, he realizes that the creature resembles, more than anything, an enormous brain cell. Kirk catches on immediately: these creatures are not separate animals, they are all parts of a single entity, connected together in some mysterious fashion. This is how it resists phaser fire: each part draws strength from the whole.

McCoy's multiple efforts to find some method to kill the creatures fail. Not heat, not radiation – nothing can kill it. Kirk knows that if they cannot find a way to kill these creatures, he will be forced to destroy Deneva to prevent their spread. A million people will die if nothing can be done. Kirk cannot let the creatures spread, and has absolutely no wish to kill the Denevans, including his nephew. He demands a third alternative.

Act FourEdit

The key lies in exploring the properties of the sun. The Denevan the Enterprise contacted earlier was free of the creature moments before he died; something in the sun killed it. It is not radiation, it is not heat – could it be light? After turning a computer in his quarters on and off, Kirk thinks that it may be the answer. McCoy rigs a test cubicle, puts the sample creature inside, and confirms the theory: high intensity light is fatal to these creatures. Spock enters next; it is necessary to see what will happen to tissue that has infiltrated a victim. Spock volunteers to enter the cubicle – McCoy, who would prefer his guinea pig be someone other than the man he regards as Starfleet's best first officer, attempts to dissuade him, but Spock insists. This test does, in fact, succeed: the blinding light completely frees Spock of the creature and the pain – but at the cost of his eyesight. Spock, exiting the cubicle, remarks that it is an equitable trade – the closest he comes to revealing how much pain he has been experiencing. Only then is the true tragedy revealed: lab tests indicate that the creatures are vulnerable only to a specific subset of the light spectrum: ultraviolet light is its Achilles' heel. McCoy is chagrined to realize that Spock need not have been blinded at all.

Despite this, the answer is at hand. Kirk orders satellite control to deploy a formation of 210 ultraviolet satellites at 72 miles altitude, in a permanent orbit. The satellites are turned on; the creatures begin to fail, to fall, to smoke and to die. Ground stations on Deneva quickly make contact; the creatures are dying everywhere.

Spock returns to the bridge – he can once again see. It seems that an inner eyelid, an hereditary trait of Vulcans, protected his eyes automatically. Relieved beyond words, McCoy asks Kirk not to mention his previous "best first officer" statement – at which point Spock turns around from his science station and thanks the doctor for his compliment, and Kirk jokes that all the concern over Spock's eyes had led McCoy to forget about his Vulcan ears. Kirk has Sulu take the Enterprise to warp factor 1 and the ship leaves Deneva.

Log entries Edit

  • "Captain's log, stardate 3287.2. The mass insanity we have tracked across this section of the galaxy seems to have already touched Deneva. That planet, colonized over a century ago, is one of the most beautiful in the galaxy."
  • "Captain's log, supplemental. Whatever the creatures are, they have apparently taken over all the inhabitants of Deneva. Meanwhile, ship's surgeon Dr. McCoy is examining a strange puncture wound left by one of the creatures on Mr. Spock's back."
  • "Captain's log, stardate 3289.8. I am faced with one of the most difficult decision of my life, unless we find a way to destroy the creatures without killing their Human hosts, my command responsibilities will force me to kill over a million people."

Memorable quotes Edit

"Pain is a thing of the mind. The mind can be controlled."

- Spock to McCoy, on his infection by a flying parasite

"Freeze right there, Mister Spock. Or I'll put you to sleep for sure."

- Scott, pointing a phaser at Spock in the transporter room

"Jim, that man is sick! And don't give me any damnable logic about him being the only man for the job."
"I don't have to, Bones. We both know he is."

- McCoy and Kirk, on Spock going back to Deneva to capture a flying parasite as a specimen

"I cannot let it spread beyond this colony even if it means destroying a million people down there."

- Kirk, to McCoy on eliminating the flying parasites inhabiting the colonists on Deneva

"I am free of it and the pain. And I'm also quite blind. An equitable trade, doctor. Thank you."

- Spock, after undergoing the bright light experiment

"My first sight was the face of Doctor McCoy bending over me."
"'Tis a pity your brief blindness did not increase your appreciation for beauty, Mister Spock."

- Spock and McCoy, on the bridge

"You've been so concerned about his Vulcan eyes, doctor, you forgot about his Vulcan ears."

- Kirk, after Spock overhears McCoy's compliment

Background information Edit

Production timeline Edit

Story and script Edit

  • This is the only episode title of the Original Series that includes an exclamation point and, along with VOY: "Bride of Chaotica!", is one of only two episodes in the entire Star Trek franchise to incorporate that particular punctuation mark. It is also the only episode of the original series to incorporate a dash in the title.
  • In addition, it is one of only three original series episodes in which the word "damn" is used, with McCoy cursing the "damnable logic" behind the experiments designed to destroy the creatures. The only other uses of the word "damn" occur in "Journey to Babel", wherein Kirk admits he can't "damn" Spock for his loyalty by taking command of the Enterprise at the cost of Sarek's life, and in "Court Martial" where Kirk makes a log entry stating that the evidence against him is "damning."
Peter Kirk, deleted scene

Deleted scene with Peter Kirk in captain's chair

  • A filmed scene cut from this episode featured dialogue between Kirk and his nephew Peter. The dialogue concerned Peter's returning to Deneva to live with Sam Kirk's partner. [1]
  • Steven W. Carabatsos had an obligation in his contract, that he must deliver at least one script of his own while serving as story editor. Carabatsos left the series in late-1966, but still had to fulfill this task before departing. Having no idea of his own, Gene Roddenberry suggested him one, entitled Operation: Destroy!, which was the basis for this episode. (These Are the Voyages: TOS Season One)
  • The script, as originally conceived, did not envision the parasites being killed with light. Instead, the Enterprise leaves Deneva and destroys their home planet. By effectively annihilating the central "brain" that controls their operations, the ship renders the creatures harmless. Working from an early draft of the script, James Blish writes up this version in his adaption of the episode in his volume Star Trek 2.
  • The first draft script, entitled "Operation: Destroy", did not feature Kirk's brother and his family. In that version, a Denevan woman named Aurelan was in love with a young man named Kartan, who flew his ship into the Sun to destroy the creatures. Aurelan and her father were not infected, and helped the Enterprise crew in their research. (The Star Trek Compendium, p. 65)

Effects Edit

Sets, locations, and props Edit

  • The Deneva outdoor scenes were shot at the headquarters of TRW Space and Defense Park in Redondo Beach, California (currently the Northrop Grumman Space Technology headquarters). See here for the location in Google Earth. The establishing shot of Kirk's brother's lab was a building on the campus of UCLA, and the entrance of the building was the cafeteria at TRW. (Star Trek Encyclopedia (2nd ed., p. 112)) The scenes at TRW were filmed 15 February 1967. [2]
  • This is the first time McCoy's lab is seen. Inside the lab, the prop used previously as Balok's lamp device in "The Corbomite Maneuver" can be seen sitting on a shelf. Different components of sickbay were added over the first season, such as the decompression chamber seen in "Space Seed". McCoy's lab contains one of the life support canisters used on the Botany Bay.
  • The chairs that were seen in Chief Vanderberg's office in "The Devil in the Dark" were recycled for Sam Kirk's office, albeit painted pink.
  • The oversized plexiglas tongs that Spock uses to pick up the Denevan parasite would again be used to recover the phasered sample of tritanium in the teaser of "Obsession".
  • The starmap showing the progression of the space madness also shows up on station viewscreens in future episodes.
  • Wah Chang designed and constructed the parasite creatures. In the Star Fleet Medical Reference Manual, it was called a "blastoneuron."
  • The clubs used by the Denevans during their attack on the landing party appear to be thick Lucite rods. (citation needededit) Curiously, the gray, grooved clubs used by Spock during his fight with Kirk in "This Side of Paradise" and some of the miners on Janus VI in "The Devil in the Dark" were not recycled for this use.
  • The white trombone mutes usually seen in the glass case of Enterprise's Sickbay are seen in the back room of Sam Kirk's lab. They are later seen in McCoy's lab.

Costumes Edit

  • Unique to this episode, Uhura wears a black belt on the bridge, having worn one while on the landing party in the previous episode produced, "The City on the Edge of Forever". In "The Gamesters of Triskelion", she dons it when she joins the landing party and wears a communicator and phaser.
  • Although the ubiquitous jumpsuit-type outfits worn by the four Denevans who attack the landing party crop up in a variety of colors, this is one of the few in which a green one appears. There is also a red variety, apparently the only one ever seen in The Original Series.

Performers Edit

  • The body of George Samuel Kirk was played by William Shatner, wearing a false mustache and a different hairstyle.
  • Stock footage of Leslie's hands from "The Alternative Factor" is used to represent the personnel in the satellite control room. This shot was removed from the remastered version of the episode.
  • William Blackburn, an extra on the show from "The Corbomite Maneuver" through the end of season three, can be seen in the background in at least three different uniforms in this episode.
  • There is a blooper from this episode in the first season blooper reel. The parasite creature that was supposed to hit Leonard Nimoy's back is seen hitting his backside instead, making Nimoy break up with laughter. Also appearing is a sequence showing the landing party with their phasers being used in tandem as electric shavers.

Continuity Edit

  • McCoy speaks about "getting the plates back" on Kirk's nephew to help with his medical treatment. This line references X-ray plates which were common in the 1960s but, in the 2260s, would have been extremely archaic and impractical compared to other medical advances of the time (such as DNA examination).
  • The Vulcan inner eyelid is mentioned again in ENT: "The Forge". In the Star Trek novel Spock's World, the inner eyelid was developed in one tribe of Vulcans who eventually took control over most of the planet.

Video and DVD releases Edit

Links and references Edit

Starring Edit

Also starring Edit

Co-star Edit

Featuring Edit


With Edit

Uncredited co-stars Edit

Stunt doubles and stand-in Edit

References Edit

2067; 22nd century; 2265; 2266; advisor; affection; "all right"; alternativve; altitude; amount; answer; appendix; archaeologist; area; arm; asteroid belt; attitude; audio; autonomic system; beauty; bee; Beta Portolan; Beta Portolan system; bio-bed; biolab; billion; blindness; Blood Q⁵; Blood T²; body; "Bones"; brain cell; building; call sign; candlepower; cargo; capital city; cell; chance; choice; civilization; club; computer; consciousness; contact; contact signal; coordinates; course; creature; curiosity; deck; degree; delirium; Deneva; Deneva (star); Deneva capital city; Deneva colony; Denevan; Denevan ship; Denevan sun; dog; ear; electromagnetic spectrum; energy; engineering advisor; engineering control; environmental control; eye; eyesight; face; fact; family; Federation; flying parasite; force 3; freighting-line base; goggles; gravimetric pull; gravity; ground station; GSK 783; heat; hereditary trait; hour; host; hull; hull temperature; Human; idea; inch; information; Ingraham B; Ingraham B vessel; inhabitant; inner eyelid; interception course; K3 indicator; laboratory; landing party; Large Magellanic Cloud; leg; Levinius V; life sciences department; light; logic; mask; mass; mass insanity; matter; medical department; mile; Milky Way Galaxy; million; mind; miner; month; nervous system; nurse; "on the hot seat"; opportunity; optical nerve (aka optic nerve); "of course"; pain; patient; pattern; permission; phaser; phaser power; physical law; physical property; place; plate; planet development; plot; population; power; private transmitter; progress; puncture; quality; question; radiation; research biologist; result; risk; satellite control; science department; science lab; section; security alert; security restraint; sedative; seeding orbit; sensor; shadow; single-celled organism; sleep; sound; specimen; speculation; spinal cord; "stand by"; Starbase 10; Starfleet Academy; straight line; stinger; street; subspace frequency three; subspace transmitter; sub-warp speed; surface; surgery; survivor; temperature; tentacle; test cubicle; "thank you"; theory; Theta Cygni XII; thing; thousand; tissue; tolerance level; tractor beam; tranquilizer; transcript; transmitting station; trap; trevium; tricorder; tri-magnesite; ultraviolet light; ultraviolet satellite; ventilator; victim; Vulcan; Vulcan (planet); Vulcan (star); Vulcan nerve pinch; wasp; white

External links Edit

Previous episode produced:
"The City on the Edge of Forever"
Star Trek: The Original Series
Season 1
Next episode produced:
Previous episode aired:
"The City on the Edge of Forever"
Next episode aired:
"Amok Time"
Previous remastered episode aired:
"The Ultimate Computer"
TOS Remastered Next remastered episode aired:
"The Apple"
Community content is available under CC-BY-NC unless otherwise noted.