The Terratin Incident (episode)
When a strange flash of light paralyzes the entire crew of the Enterprise, they begin to shrink. Kirk beams down to the nearest planet, Cepheus, and discovers a miniature race (of descendants of a lost Earth colony) desperate to leave their volcanic homeworld.

Summary
"Captain's log: Stardate 5577.3. We are approaching the remains of the burned out supernova, Arachna. Requested updated survey will begin with measurements of its radiation and volume expansion."

Spock reports from his station that Arachna has reached its cycle of strongest emissions. Kirk orders "Uhura, inform Starbase 23 we have arrived at the gas cloud and are starting to map." The  receives a garbled message. Uhura reports interference and there is only one comprehensible portion of a signal, which emanates from the star Cepheus, although that particular area has not produced any radio transmissions before. Transmitting in intersat code, a code that has not been used in centuries, is the word 'terratin.' 

Kirk has Sulu set course for Cepheus. Upon the Enterprises arrival and subsequent investigation, the starship encounters a planet of crystalline structure, barraged by volcanic activity. While in orbit, a flash of light passes through the ship, paralyzing the crew. Scotty reports that the dilithium crystals are unpeeling like the rind of an  and all connections are busted. Kirk asks, "Spock, are you slumping?" The Vulcan replies, "I have never slumped in my life, captain, but I was about to ask you the same…" Kirk interrupts and insists the ship must get away from the planet as fast as possible. 

"Captain's log, stardate 5577.5. Our limited power attempt to escape the planet's gravity has failed. Undefined wave bombardment continues resulting in a contraction of our bodies or an expansion of the ship by a factor of 0.3."

Uhura reports, "No reply to our mayday, captain. I don't believe we have enough power to transmit to Starbase 23." Kirk asks McCoy for answers. He shows Kirk that they are indeed degenerating. The space between the molecules of their body is diminishing so they retain their original weight. Spock notes all organic matter on the ship is shrinking. 

"Captain's log, stardate 5577.7. We will lose effective control of this vessel at the point when we have become one centimeter tall. At the present rate we will reach this less than fingernail length in 32 minutes."

Spock calculates that in a matter of minutes the entire crew will stand 1/16 inch high, well past the operative point of ship's controls. By using man-made ladders, the crew manages to get to their consoles and use their collective strength to press the transporter buttons. Kirk orders Scott to set automatic return for him in ten minutes. Kirk then orders Scott that a crew be sent down to the transporter room to beam himself down to the surface. Upon materialization on the surface of the planet, Kirk immediately grows back to full size, since the transporter retained a memory of his body's molecular structure and changed it to previously detailed size and shape. 

While on the planet, Kirk encounters a miniature city, but is beamed back to the ship by the transporter's automatic settings. Upon returning, he discovers that his bridge crew has been transported off the ship to the planet's surface. Kirk opens a channel and threatens the city with all the ship's armament locked onto it if his crew is not immediately returned unharmed. The leader, the Mendant, informs Kirk that the lightning attack was the only way he could get the full attention of the starship, and apologizes. He informs Kirk that their city is being threatened by volcanic activity and their adoptive planet is dying. 

Spock discovers the Terratin natives to be mutated descendants of a missing early scientific expedition; the survivors named the planet Terra Ten. The crew is transported back to the ship, but since the Terratins cannot be restored to the size of their ancestors, they and their entire city are beamed aboard the Enterprise to be taken to a more stable planet. The leader shows the appreciation of all Terratin inhabitants by naming all the Enterprise crew honorary Terratins now and for all time to come. Spock notes "We came rather close to more than honorary." Kirk says, "Yes, I'd say just about a sixteenth of an inch close."

"Captains log, supplemental. The Lilliputian city is to be taken to Verdanis and relocated on a fertile and well watered plain. Then we'll be able to call the Terratin Incident closed."

Log entries 
 Captain's log, USS Enterprise (NCC-1701), 2269

Memorable quotes
"Spock – are you slumping?"
"I have never slumped in my life, captain."
 - Kirk, noticing that Spock is getting smaller

"Visual sweeps are already impossible, sir. My eyes no longer fit the opticals."
"And I can't reach the dial I turned five minutes ago!"
 - Lieutenant Arex and Uhura

"We've got twenty-nine minutes before we're too small to operate ship controls!"
 - Kirk

"Spock's theory is right, we're contracting."
"That's why our weight remains the same. Same number of atoms. The effect is just reducing the space between the molecules. It's something I've never seen before."
 - Kirk and McCoy

"What is the composition of this decoration?"
"It was an arm bracelet, more like a necklace now."
"Yet the uniform on which you wear it fits as well as ever. Uniform made of algae-based xenylon, I believe."
 - Spock and Nurse Chapel

"Scotty, is it you?"
"Aye, captain. For the love of heaven, be careful where you step!"
 - Kirk, restored to normal height, finds Scott the size of a dot on the bridge

Background information

Story and Script
 This episode's writer, Paul Schneider, previously wrote two  episodes:  and . According to Schneider, "The 'Terratin Incident' was based on a one-paragraph story idea that Gene Roddenberry had. I took it from there with Dorothy Fontana, the show's associate producer. I just loved the concept of doing something related to . I enjoyed that, as well as watching the process of animation develop. Overall, I thought the episode turned out rather well." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 98)
 The editors of Trek magazine collectively scored this episode 2 out of 5 stars (a rating that they termed "fair"). (The Best of Trek #1, p. 110)
 In the unofficial reference book Trek Navigator: The Ultimate Guide to the Entire Trek Saga (p. 236), co-writer Mark A. Altman rates this episode 2 out of 4 stars (defined as "mediocre") while fellow co-writer Edward Gross ranks the episode 2 and a half out of 4 stars (defined as "average").

 In 's "Ultimate Guide" (), this episode was rated 3 out of 5 Starfleet arrowhead insignia.
 The idea of some of the crew being miniaturized by a form of scientific phenomenon was used twice: Once by Flint on the Enterprise in , second in  had shown a miniature model of the Enterprise, upon which  had used "magic" to come close to destroying the ship, and again in , wherein Jadzia Dax, Julian Bashir, and Miles O'Brien are all reduced in size and then have to save the  from the Jem'Hadar while in a similarly reduced runabout.
 One of the Terratin colonists appears to be a re-use of the animation for Carter Winston.

Video and DVD releases
 UK VHS release (CIC Video): Volume 5, catalog number VHR 2539, 
 As part of the The Animated Series DVD collection
 As part of the The Animated Series Blu-ray collection

Apocrypha
The Star Fleet Medical Reference Manual identifies the radiation used for reducing the characters in size as epsilon rays. It explains that this radiation's effects cannot be reversed without the use of such matter-rearrangement processes as matter transporters and that prolonged exposure causes extremely small bodies (which it approximates at 0.16 cm for Humans)  to become a genetic trait.

Alan Dean Foster's prose conversion, in Star Trek: Log 4, tells of the planet Verdanis being renamed Verdantin, and ends with Kirk and McCoy discussing the future of the former Terratin inhabitants.

Links and references

Starring the voices of
 William Shatner as Kirk
 Leonard Nimoy as Spock
And
 DeForest Kelley as McCoy

Also starring the voices of 
 George Takei as Sulu
 Nichelle Nichols as
 Uhura
 Briel
 Majel Barrett as Chapel
 James Doohan as
 Arex
 Scott
 Gabler
 Mendant of the Terratins

Guest background characters 
 Herb Hazelton as a command lieutenant 2 (no lines)
 Bob Kline as a sciences lieutenant 2 (no lines)
 George Jensen as a sciences lieutenant 3 (no lines)

Background characters 
 Two Enterprise engineers (too small for their tools)
 Enterprise engineer 1
 Enterprise engineer 2
 Five Enterprise crew (in mess hall)
 Command lieutenant 1
 Sciences lieutenant 1
 Operations lieutenant commander
 Kyle
 Three Enterprise engineers (in transporter room/bridge)
 Three Enterprise engineers
 Twenty-two Terratin inhabitants

References 
2069; 21st century; 2277; ability; aquarium; algae; analysis; ancestor; answer; apology;  Arachna; area; area status light; armament; ash; atmosphere; atom; automatic return; body; bone-knitting laser; "Bones"; bracelet; bridge crew; bridge report; bulkhead; ; bypass; cage mesh; capitol building; casualty; ; centimeter; Cepheus; chair; choice; class M; climbing; code word; colony; color; communicator; composition; compound fracture; computer; computer banks; console top; contact; coral; corruption; course; crust; crystal; cycle; damage; damage report; ; deafness; ; departure; deflector shield; descendant; dial; dilithium; dilithium crystal connection; dilithium supplies; distance; DNA; double helix; ear; Earth; effect; electric eye; elliptic orbit; emission; engine; experience; exploration; eye; fall injury; fertility; fingernail; fire pattern; "for the love of heaven"; frequency; gas cloud; geographic center; "good luck"; gossamer mouse; gravity; great antenna; green light; hairpin; halo fish; harm; height; home; honorary; impulse power; "in case"; inch; information; infrared; inhabitant; injury; "in other words"; insult; intelligence; interference; intersat code; "in the name of"; invasion defense antenna; jury rig; kittens; ; knowledge; lab; lab animal; lab shelf supplies; land; Latin language; lava flow; leg; Libra; Lilliputian; long chain molecule; macroscope; main circuit; main dining room; mantle; mapping mission; mayday; measurement; mendant; message; mess officer; meteoritic rock; microscope laser; middle ear; miniature laser; miniaturization; minute; molecular structure; molecule; name; nature; necklace; nitrogen; "no way"; nucleus; number; odds; organic matter; ; ounce; outsider; oxygen; panic; permission; phaser; place; plain; planetary core; pride; problem; purr ("purring like happy kittens"); question; radiation; radio source; radio transmission; range; readout; reply; rescue; research; result; rind; ring; ; sensor; sensor sweep; ship area; shock; signal; silverware; size; smoke; speaker; splint; spiroid epsilon wave; spiroid wave analysis; star; Starbase 23; ; subspace extreme upper register; subspace radio; supernova; survival; switch; table; tadpole; Terra 10; Terratin; Terratin city ("Lilliputian city"); test tissue; theory; thing; timer; titanium; titanium smith; tool; transporter beam; transporter controls; transporter mechanism; Transporter Room 3; Verdanis; volcanic activity; volcanic eruption; ; warp engine circuitry; weight; word; word pattern; xenylon; x-wave

External links 
 
 
 
 

de:Die Rettungsmission
es:The Terratin Incident
fr:The Terratin Incident (épisode)
nl:The Terratin Incident
Terratin Incident, The