The Enterprise crew finds happiness at a colony where alien spores provide total contentment.
The USS Enterprise arrives at the planet Omicron Ceti III, the site of a colony established in 2264. Unfortunately, the Enterprise's mission is only to catalog its destruction under the bombardment of deadly berthold rays, which were discovered after the colonists left Earth.
Captain Kirk, Commander Spock, Doctor McCoy, Lieutenant Sulu, Lieutenant DeSalle, and Lieutenant Kelowitz beam down to the planet's surface to surprisingly discover that Elias Sandoval and the other colonists are not dead after all. Spock encounters Leila Kalomi, a botanist he had met on Earth many years before. She had loved him, but he had been unable to return her love. McCoy is astounded to discover that every colonist is in perfect physical health, even to the point where childhood injuries have repaired themselves. Sandoval attributes this to their healthy lifestyle that is a plant based diet. Other anomalies are discovered, such as the total lack of any animal life other than the colonists themselves.
Leila promises to tell Spock their secret, and leads him to a flowering plant, which blasts him with spores. The spores cause Spock's emotional barriers to break down, and he confesses his love for Leila. When Kirk hails Spock, he does not respond, forcing Kirk to come and find out what is wrong. Spock manages to blast Sulu and Kelowitz with spores as well, and soon McCoy is beaming the plants aboard the Enterprise.
As it turns out, the spores not only induce a feeling of total peace and euphoria, but they are also the reason that the colonists have been protected from the berthold rays. Spock explains that the plants traveled through space until they landed on the planet, actually thriving on the berthold rays. The plants act as a repository for thousands of microscopic spores until they find a Human body to inhabit. In return, they give their host complete health and peace of mind: in short, paradise; no wants and no needs. When Kirk hears that, he disagrees, stating that Humans weren't meant for that. He insists that man stagnates if he has no challenge to drive him and motivate him. But Spock says that Kirk simply doesn't understand now, but that he would come around eventually and really comprehend what they mean and join them.
Kirk, however, decides to go back to the ship. Uhura, under the spores influence herself, leaves the bridge to beam down, but not before sabotaging the communications station so Kirk cannot contact Starfleet, only to be in contact with the planet. Alone on the bridge and growing increasingly desperate in his situation and realizing the helpless position he is in as the last person unaffected by the spores, he records a message on the log, confessing to his isolation and his inability to offer something against this alluring paradise, when he is suddenly blasted by a pod plant left on the Enterprise bridge. He becomes just as mindlessly happy as the others and hails Spock to let him know that he finally understands and wants to join them after all. About to beam down on the planet, he suddenly gets a hold of himself and becomes angry, yelling that he cannot leave and becomes himself again, free of the spores. That is when he realizes that violent emotions and anger are what counteract the spores' euphoria-inducing effects. Noting this cure for the spores in his log, Kirk also realizes that his plan to free his crew and the colonists from the spores' effects comes with one potential danger: Spock. Knowing his First Officer to be stronger than a normal human being, and could kill him with his bare hands, Kirk decides to risk it as he successfully tricks him into beaming up, and angers the Vulcan sufficiently enough to destroy the spores in his body as well. When Spock comes to, the two create a subsonic transmitter that induces anger and intense emotions in everyone on the planet's surface, thus eradicating the spores.
When Leila beams up to the ship to find out what happened to Spock, she tells him that she cannot lose him again, but Spock tells her that has a responsibility to the ship and to that man on the bridge. He goes on to tell her that he is who he is, and that if there are self-made purgatories, and they all have to live in them, his cannot be worse than someone else's. Leila cries and then realizes that she lost not only Spock but the feeling the spores induced as well. However, she says that her feelings for Spock still have not changed and that she still loves him.
The transmitter is activated, and fights break out across the colony, destroying the spores' effects. Sandoval expresses regret, noting that they have not really accomplished anything, as any progress they made was purely the result of the spores. He hopes that he and the other colonists can try again on another planet. As the Enterprise leaves Omicron Ceti III for Starbase 27, McCoy cynically states that this is the second time humans have been thrown out of paradise and Kirk responds jokingly that actually this time they just walked out on their own; maybe they weren't meant for paradise, says Kirk, maybe they were meant to fight their way through, struggle and scratch for every inch of the way. Spock, on the other hand, realizes that his time with Leila on the surface was the first time he had ever been happy.
- "Captain's log, stardate 3417.3. We thought our mission to Omicron Ceti III would be an unhappy one. We had expected to find no survivors of the agricultural colony there. Apparently, our information was incorrect."
- "Captain's log, supplemental. We have been ordered by Starfleet Command to evacuate the colony on Omicron III. However the colony leader, Elias Sandoval, has refused all cooperation and will not listen to any arguments."
- "Captain's log, stardate 3417.5. The pod plants have spread spores throughout the ship, carried by the ventilation system. Under their influence, my crew is deserting to join the Omicron colony and I can't stop them. I don't know why I have not been infected, nor can I get Dr. McCoy to explain the physical-psychological aspects of the infection."
- "Captain's log, stardate 3417.7. Except for myself, all crew personnel have transported to the surface of the planet, mutinied. Lieutenant Uhura has effectively sabotaged the communications station. I can only contact the surface of the planet. The ship can be maintained in orbit for several months, but even with automatic controls, I cannot pilot her alone. In effect, I am marooned here. I'm beginning to realize... just how big this ship really is. How quiet. I don't know how to get my crew back, how to counteract the effect of the spores. I don't know what I can offer against... paradise."
- Captain's log, supplemental. I think I've discovered the answer. But to carry out my plan entails considerable risk. Mr. Spock is much stronger than the ordinary Human being. Aroused, his great physical strength could kill. But it's a risk I'll have to take."
"On pure speculation... just an educated guess – I'd say that man is alive."
- - Dr. McCoy, about Sandoval
"It's like a jigsaw puzzle, all one color. No key to where the pieces fit in. Why?"
- - Kirk
"Get back to your stations... get back to your stations!"
"I'm sorry sir, we're all transporting down to join the colony."
"I said get back to your stations!!."
"This is mutiny, mister!"
"Yes, sir, it is."
- - Kirk and Leslie
"No , don't... No, please!"
"It shouldn't hurt; not like this, it didn't hurt us."
"I am not like you."
- - Spock and Leila, as Spock reacts to the spores
"I love you... I can love you!"
- - Spock, after being infected with the spores
"Hey, Jim-boy – y'all ever had a real, cold Georgia-style mint julep, huh?"
- - McCoy, reacting to the spores
"Who wants to counteract paradise, Jim-boy?"
- - McCoy, reacting to the spores
"Man stagnates if he has no ambition, no desire to be more than he is."
- - Kirk
"No... No... I - can't - LEAVE!"
- - Kirk, freeing himself from the influence of the spores
"All right you mutinous, disloyal, computerized half-breed, we'll see about you deserting my ship."
"The term 'half-breed' is somewhat applicable, but 'computerized' is inaccurate. A machine can be computerized, not a man."
"What makes you think you're a man? You're an overgrown jack rabbit, an elf with a hyperactive thyroid."
"Jim, I don't understand."
"Of course you don't understand. You don't have the brains to understand. All you have are printed circuits."
"Captain, if you'll excuse me."
"What can you expect from a simpering, devil-eared freak, whose father was a computer and whose mother was an encyclopedia?"
"My mother was a teacher, my father an ambassador."
"Your father was a computer, like his son. An ambassador from a planet of traitors. The Vulcan never lived who had an ounce of integrity."
"Captain, please don't."
"You're a traitor from a race of traitors, disloyal to the core, rotten like the rest of your sub-Human race – and you've got the gall to make love to that girl."
"Does she know what she's getting, Spock? A carcass full of memory banks who should be squatting on a mushroom instead of passing himself off as a man. You belong in a circus, Spock, not a starship – right next to the dog-faced boy."
- - Kirk and Spock
"Had enough? I never realized what it took to get under that thick hide of yours. Anyhow, I don't know what you're so mad about – it isn't every first officer who gets to belt his captain... several times."
- - Kirk, after Spock is free of the spores
"Captain, striking a fellow officer is a court-martial offense."
"Well, if we're both in the brig, who's going to build the subsonic transmitter?"
(considers) "That is quite logical, captain."
- - Spock and Kirk
"I am what I am, Leila, and if there are self-made purgatories, then we all have to live in them. Mine can be no worse than someone else's."
"And this is for my good? Do you mind if I tell you I still love you? You never told me if you have another name, Mr. Spock."
"You couldn't pronounce it."
- - Spock and Leila Kalomi, free of the spores
"We don't need you any more – as a doctor."
"Oh no? Would you like to see just how fast I can put you in a hospital?"
- - Elias Sandoval and McCoy
"Maybe we weren't meant for paradise. Maybe we were meant to fight our way through – struggle, claw our way up, scratch for every inch of the way. Maybe we can't stroll to the music of the lute. We must march to the sound of drums."
- - Kirk
"... for the first time in my life, I was happy."
- - Spock
"... no horses, no pigs, not even a dog!"
- - Sulu
Story and script
- The title comes from the old adage used to denote that a certain area is second only to Paradise (Heaven), for example, "Southeastern Kentucky is the most beautiful spot this side of Paradise." It was also the title of F. Scott Fitzgerald's first published novel.
- In Jerry Sohl's original draft (first titled "Power Play," then "The Way of The Spores"), it was Lieutenant Sulu who was infected by the spores and was able to fall in love with Leila.
- In the script, Kirk first spots Spock and Leila kissing passionately by the stream; there is no scene of Spock hanging off the tree limb. That facet of the episode may have been made up on the spot.  Indeed, director Ralph Senensky came up with the idea of Spock hanging from the tree on location, when he found the tree and the spot closely to Bronson Canyon. Originally the scene was to be shot on a clearing. 
- Leila Kalomi says she has "never seen a starship before". But then how did she get to the colony from Earth?
- What happened to the livestock is never fully explained.
Cast and characters
- James Doohan (Scotty) does not appear in this episode, although he is referenced and asked for by Kirk - ironically, when Doohan appeared in TNG: "Relics" 25 years later, the shot from this episode of Kirk walking onto the empty bridge was used as Scotty's entrance in to the holodeck simulation of it.
- Bobby Bass, who tries to break up the fight between Kelowitz and the crewman played by Ron Veto, has his only lines of dialog in the series here. Usually a stuntman on the series, he can also be seen as the guard Khan knocks out in "Space Seed", as one of Chekov's henchman in "Mirror, Mirror" and as a Klingon in "Errand of Mercy".
- Frank Overton died shortly after completing this episode, which was filmed in early January 1967.
- This is the last episode in which Eddie Paskey delivers dialog as Leslie.
- Admiral Komack is mentioned in this episode; he is seen in "Amok Time". According to Denise and Michael Okuda, the character was named for James Komack, director of "A Piece of the Action".
- Leonard Nimoy has related that Charles Bronson, then Jill Ireland's boyfriend and later her husband, was constantly on location, jealously watching his and Ireland's love scenes being filmed. (citation needed • edit)
- The location where Leila and Spock discuss the dragons of Berengaria VII can be seen again in TNG: "Descent". It is in Bronson Canyon, near the famous Hollywood sign.
- The large open meadow seen in several sequences is in the Santa Ynez valley in southern California. It is the same spot where the hunt in the corn field took place in Planet of the Apes. It was also extensively used in the series Gunsmoke.
- The barn Kelowitz and Sulu investigate can be seen in several episodes of Kung Fu.
- The buildings seen in the teaser, the first scene after and the scene in which DeSalle shows McCoy the Spores are at a different location than the buildings seen in the rest of the episode. The green farm structures were located at the Disney Ranch. The concept of Sandoval's people refusing modern technology was intended to justify the late-19th century Americano style of the ranch. 
- According to director Ralph Senensky the original schedule was that the first three of the six shooting days were to be spent on location, shooting at Disney Ranch, then the remaining three days indoors, filming the Enterprise scenes. However, after two days of shooting outdoors, Jill Ireland fell ill and couldn't appear on the set. It was in question if she had measles or not. Senensky decided to film all the farm scenes which didn't contain Leila's character in the remaining one day and hope for the actress' return. Ireland appeared the following day, as it turned out that she's not having measles. However, the crew couldn't return to Disney Ranch as it was already booked for another production. They decided to film the remaining scenes at Bronson Canyon. 
Sets and props
- The food processors in the transporter room, placed there so Kyle could provide chicken soup for the air sergeant in "Tomorrow is Yesterday", disappeared from the room by the end of the first season. In this episode, an enraged Spock destroys one of them.
- There is a piece of equipment attached to the left side of the transporter console. It seems to serve no purpose, other than for Spock to hit when he misses Kirk during their brief dust-up, and was only seen in this episode. In fact, it was not in the scene where six crew members, under the influence of the spores, transport down.
- The plant that sprays Kirk with spores on the bridge is the one he flung in anger after Uhura shorted out the communications console, however, in the wide bridge shots, there is no plant visible.
- Kirk packs his belongings in a very twentieth-century type of suitcase of the Samsonite variety. Its inclusion dates the episode, as this type of suitcase is rarely used even today.
- The spore-spraying plants in this episode look and behave almost exactly like the ones from "Specimen: Unknown", a 1964 episode of "The Outer Limits" which was directed by Gerd Oswald and featured Arthur Batanides and celebrity Trekkie Russell Johnson.
- In an homage to "This Side of Paradise", a 2002 episode of "Smallville" called "Nicodemus" featured plants which have the appearance and anti-repressive power of the ones from this episode.
- The preview for this episode shows Leila and Spock by a stream. This didn't survive in the final cut of the episode.
- The empty shot of the bridge, before the turbolift opens to admit Kirk, was the best available piece of film for TNG: "Relics" to reuse as the holosimulation of the NCC-1701 bridge. The short snippet of film was "looped" several times and bluescreened in behind James Doohan and Patrick Stewart's scenes. Using the stock footage in this way eliminated the need to completely rebuild the bridge – they only built a short section of the computer stations, the door alcove and the command stations for the TNG-era actors to sit at.
- In a blooper, Leonard Nimoy flubs his line about the plants acting as a repository for thousands of spores. Instead, he says the plants act as a "suppository." The crew cracks up, as does Nimoy, who caps the fun by putting a Tootsie Pop in his mouth.
- DeSalle wears the yellow shirt of a member of the command division, not the blue shirt of the sciences section, yet he delivers the planet's biology report to Kirk. This is especially odd considering that the blue-shirted Kelowitz was a member of the landing party.
- In "The Tholian Web", Chekov asks Spock if there has ever been a mutiny on a starship before. Spock replies that there has never been. Since it is explicitly stated that mutiny is committed in this episode, Chekov and Spock may have been talking about violent mutinies.
- Treatment by Jerry Sohl, 15 June 1966
- Treatment by Jerry Sohl, July 1966
- Treatment by Jerry Sohl, 9 August 1966
- Second draft teleplay by Jerry Sohl, 11 October 1966
- Treatment by D.C. Fontana, 15 November 1966
- First draft teleplay by D.C. Fontana, 7 December 1966
- Final draft teleplay, 15 December 1966
- Revised final draft teleplay, 28 December 1966
Video and DVD releases
- Original US Betamax release: 1985
- UK VHS release (two-episode tapes, CIC Video): Volume 14, catalog number VHR 2307, release date unknown
- US VHS release: 15 April 1994
- UK re-release (three-episode tapes, CIC Video): Volume 1.9, 30 December 1996
- Original US DVD release (single-disc): Volume 13, 11 July 2000
- As part of the TOS Season 1 DVD collection
- As part of the TOS Season 1 HD-DVD collection
- As part of the TOS Season 1 Blu-ray collection
Links and references
Special guest star
- Grant Woods as Kelowitz
- George Takei as Sulu
- Nichelle Nichols as Uhura
- Michael Barrier as DeSalle
- Dick Scotter as Painter
- Eddie Paskey as a crewman
- Bobby Bass as Crewman #2
- William Blackburn as Hadley
- Frank da Vinci as:
- John Lindesmith as Engineer #2
- Jeannie Malone as a yeoman
- Sean Morgan as Harper
- Fred Shue as Crewman #1
- Ron Veto as Harrison
2261; 2263; 2264; admiral; agriculture; ambassador; appendectomy; appendix; bean; Berengaria VII; berthold rays; biochemistry lab; biology; butterfly net; circus; climate; cloud; cow; dog; dog-faced boy; dragon; drum; Eden; elf; encyclopedia; Georgia; grain; Grayson, Amanda; horse; hyperactive thyroid; insect; itching powder; jackrabbit; jigsaw puzzle; Komack; lute; mechanic; mint julep; Mira; Mira system; mushroom; mutiny; Omicron Ceti III; Omicron colony; Omicron pod plant; Omicron spore; pig; pneumonia; potato; rain; rainbow; rib; Sarek; scientist; soil; Starbase 27; Starfleet Command; Starfleet Medal of Honor; subsonic transmitter; teacher; tonsil; vegetarian; ventilation system; Vulcanian
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