(written from a Production point of view)
Voyager, desperately low on fuel, finds deuterium on a highly hostile "Demon class" planet.
The USS Voyager is running out of deuterium as a fuel and is forced to go into Gray mode. Tom Paris estimates that they have less than a week's worth of deuterium left, even if they travel at one-quarter impulse. Captain Kathryn Janeway orders Tuvok and Chakotay to brainstorm energy conservation methods while she and Harry Kim try to synthesize an alternate fuel in the Geophysics lab.
Tuvok evacuates the crew from crew quarters and instructs them to bring only essential personal items, in the interest of conserving space. He confiscates Neelix's copy of the Selected Works of Jirex as well as his pillows and blankets, which Neelix claims he needs because Starfleet bedding gives him neck pains and a rash. Tuvok tells Neelix to ask The Doctor for an anti-inflammatory and some anti-itch cream and Neelix grumbles that he might as well sleep in sickbay...and then thanks Tuvok for giving him an idea.
Seven of Nine is still working in astrometrics despite having been ordered to shut down the lab an hour ago, due to lack of power. Chakotay tells her that this is inefficient but Seven counters that efficiency is relative, since she has discovered a planetoid .4 light-years away rich in deuterium, which conventional scanners would not have detected. Chakotay identifies the planetoid as Demon class, too toxic and volatile to even enter a standard orbit. Seven responds by telling him that they are desperate and need the deuterium no matter what they have to do.
- "Captain's log, supplemental. I've ordered adaptations to our shields to repel the thermionic discharges. Hoping that the benefits will outweigh the risks, we're now trying to beam deuterium from beneath the planet's surface."
Tuvok estimates that if they tried to send a probe to collect the deuterium, it would incinerate upon entering the atmosphere and Janeway, discouraged and out of options, orders Paris to resume their previous course at one-quarter impulse. Kim suggests taking a modified shuttle to the surface and mining the deuterium from there. Tuvok and Janeway object that the planetoid's atmosphere could kill him within minutes if his environmental suit corroded and that they wouldn't be able to communicate with him or transport him off the surface until the transporters were repaired. Kim says he knows the risks and volunteers Paris to join him.
After the meeting, Paris remarks on Kim's sudden attitude change. Kim says that he has realized that with all the experience he has accumulated on Voyager in the past four years, he has no reason to act "green" anymore or to be afraid to voice his opinions. Paris asks Kim to leave him out of it the next time he decides to assert himself, because he hates hot weather.
Kim and Paris land their shuttle on the planet's surface and search for the deuterium. They find a cavern with a pool of thick, metallic liquid, packed with deuterium, with other pools nearby. Paris goes to check out another one while Kim collects samples. Paris jokes about setting up some lounge chairs and a beach umbrella and having a nice vacation, and realizes that Kim isn't responding to him. He returns to the pool and finds that Kim has fallen in – Kim says he felt like he was pulled in. The computer in Kim's environmental suit warns him that a seal has been compromised and he will be deprived of oxygen in thirty seconds. As Paris tries to get him back to the shuttle, his suit also breaches. They collapse on the planet's surface.
The Doctor is not happy that Neelix and a few other officers are trying to set up makeshift quarters in sickbay. He calls Chakotay down to complain but he is unsympathetic and threatens to shut down The Doctor's program to save power. The Doctor grudgingly tells Neelix and his friends to make themselves at home.
On the bridge, Janeway and Tuvok are trying to scan for Paris and Kim, who haven't returned from the surface. Janeway isn't willing to risk sending down another shuttle and sees no alternative but to land the ship. The landing severely damages many of the ship's systems, as well as depleting so much of their remaining fuel that they will not be able to take off again. Janeway orders repair crews sent out and sends Chakotay to look for Paris and Kim.
Lieutenant B'Elanna Torres tries to get Chakotay to take her along on the search and rescue mission but Chakotay tells her that he needs cool heads and that she's too personally involved. She asks him to take Seven instead.
In sickbay, Neelix tries to sleep while The Doctor noisily goes about his routine. After he threatens to start a sing-along, The Doctor allows him to turn off the lights.
On the surface, Chakotay and Seven find Paris and Kim's shuttle, unoccupied. Their tricorders don't pick up any life signs, so they follow the footprints instead. Chakotay falls after a cliff gives way and is barely able to keep from going completely over. Seven grabs him but is unable to pull him up. At that moment, Paris arrives to grab Chakotay's other hand and pull him up, without his environmental suit.
Paris tells Chakotay and Seven that after he and Kim passed out, they woke up able to breathe the planet's air. He invites Chakotay and Seven to take off their helmets and try it but Chakotay isn't willing to take any risks. They go to find Kim, who is further inside the cavern.
Meanwhile in engineering, Torres and Ensign Vorik try to keep Voyager's systems running. Vorik estimates that the transporters will be repaired within an hour but that life support will fail in two hours.
Seven and Chakotay eventually find Kim in the cavern, also without his suit. He and Paris have already collected twenty kilos of deuterium and Kim is eager to stay on the planet and keep working but Chakotay insists on returning to Voyager.
The Doctor, now with patients incoming, happily ejects Neelix and his other unwanted guests from sickbay to make room for Paris and Kim.
The away team is beamed aboard but, surprisingly, Paris and Kim start to suffocate when they materialize in the transporter room. Janeway orders them beamed to sickbay, where The Doctor establishes a force field around two of the biobeds and fills it with the planet's atmosphere so that Paris and Kim can breathe.
- "Captain's log, supplemental. The Doctor continues to investigate Tom and Harry, whose condition seems as serious as it is strange."
In sickbay, The Doctor has found a silver fluid in Paris and Kim's blood and supposes that they have been "bioformed" to survive on the demon planet. The Doctor doesn't know how to reverse the process and Voyager can't safely replicate the planet's atmosphere, which means that if Paris and Kim's condition can't be treated, they will have to be left behind when Voyager leaves.
Janeway sends Chakotay and Seven back to the surface for more information and Kim volunteers to help them while Paris stays on the ship to play guinea pig for The Doctor. Janeway intends to study the silver fluid with Torres in the meantime.
On the surface, Seven finds the planetoid decidedly unappealing but Kim calls it "breathtaking". Where Seven sees monochromatic rocks and dust, Kim sees "a dozen shades of red and gold" and says that he feels connected to the planet. Seven's tricorder detects humanoid life signs. They immediate head for them. They follow it through the caves and are surprised to find another Kim and Paris, now in their suits as they had collapsed before. The previous Kim does not seem to know.
In Voyager's science lab, Janeway and Torres analyze the silver fluid. Along with deuterium and dichromates, they discover that it has organic properties, a protein. Suddenly, the sample oozes onto Torres' thumb and, when she puts her hand back down, it creeps off her and duplicates it exactly.
Suddenly, a pool of the silver fluid forms underneath the ship and begins to sink Voyager. Janeway orders an emergency ascent and Tuvok contacts the away team to beam them back. They tell him that their party now has five members, so Janeway has them beamed directly to sickbay as a group using a wide transporter beam. Oddly, the unsuited Kim doesn't want to leave the planet and runs away.
Janeway and Tuvok try to get Voyager back into orbit but the ship is being restrained by an electromagnetic force. When they try to compensate, the thrusters overload and go offline. Decks 14 and 15 get submerged.
The ship continues to sink and Janeway determines she needs thrusters. She calls engineering, where Vorik answers that Torres is already working on repairing the thrusters but it will take at least half an hour. Instead, Janeway orders Tuvok to work on firing on the fluid with a nadion pulse in order to disperse the fluid while she checks on Paris and Kim in sickbay.
There, The Doctor has successfully resuscitated the real Paris and Kim, but can't explain why there are two identical Parises there. Janeway offers an explanation: the silver fluid has mimetic properties. It sampled Paris and Kim's DNA and created duplicates with identical memories and personalities but with the ability to survive on the planet. She asks the duplicate Paris for information, but he doesn't seem to know anything and pleads with her to go back to the planet.
Tuvok is ready with the nadion burst and tries to disperse the silver fluid. Immediately, the duplicate Paris seems to have been affected as well and doubles over. Further, the duplicate Kim hails Janeway from the surface and begs her to stop. Janeway responds that needs more information from Kim, but he still says he doesn't know anything, only a feeling. She orders the duplicate Kim beamed aboard to force him to help her figure it out.
The duplicate Kim, after a few more nadion bursts and a threat from Janeway to release the ship, forced into the situation, starts to admit a few things he begins to realize. He is connected to the planet, and, further, they need the Voyager. He continues, explaining that the "Silver Blood" is alive and has experienced sentience for the first time after duplicating Paris and Kim. The Silver Blood wants to duplicate the rest of Voyager's crew and populate the planet. Janeway gets the duplicate Kim to release the ship on the condition that she allows any willing crew members to be duplicated before they leave.
Voyager is finally able to lift off and the Silver Blood duplicates watch them go.
"Anybody's got any other ideas, I'm listening."
"We could set up a bicycle in the Mess Hall, attach a generator; pedal home?"
"Now why didn't I think of that?"
"...and I volunteer Harry to take the first shift!"
- - Janeway and Paris
"Efficiency is relative, Commander."
- - Seven of Nine
- - Harry Kim and Tom Paris, reflecting on their time in the Delta Quadrant
"When faced with desperate circumstances, we must adapt."
- - Seven of Nine, to Chakotay
"Need I remind you, Ensign, that there is no environment less hospitable to Human life than a Class Y?"
"Actually, Tuvok, no, you needn't remind me."
- - Harry Kim and Tuvok
- - The Doctor to Neelix
"I think we're through the worst of it! Almost!"
- - Chakotay
"Apparently he has adapted."
- - Seven of Nine, referring to Tom Paris' ability to breathe the planet's atmosphere
"We should have transporters back online within the hour."
"Well, that's great, but right now I'm more concerned with little things like, oh, I don't know, say, life support?"
"Indeed. According to my calculations, environmental systems will cease to function in two hours."
"You say that like you're giving me the weather report."
- - Vorik and Torres
"I could give you a litany of damaged systems, Captain, but suffice it to say, now that we're down, we won't be going up again soon."
- - Janeway and Tuvok right after landing Voyager on the planet
"Looks like they went this way."
"My tricorder isn't picking up any life signs. How did you reach that conclusion?"
"Footprints. -- I guess you never assimilated any Indian scouts..."
- - Chakotay and Seven of Nine searching for Tom and Harry in the caves
Story, script, and characters
- The evolution of this installment took place after the conception of an undeveloped episode of Star Trek: Voyager, involving the "Silver Blood" duplicates of Voyager's crew being welcomed back to the Alpha Quadrant as if they were the starship's crew. (Star Trek: Action!, p. 5)
- This episode had the working title "Demon Rock". 
- One of the primary points of inspiration for the episode was that it allowed Star Trek: Voyager's writing staff to feature a planet that was very different from the class M worlds commonly shown in Star Trek. "We thought it was time to run into a planet that was actually hostile to Human life," co-executive producer Brannon Braga recalled, "but holds some mysteries and alien secrets." (Cinefantastique, Vol. 30, No. 9/10, p. 110)
- Writer/producer Kenneth Biller described the concept of crew members being physically altered to adjust to a drastically different environment – what The Doctor calls here "bioforming" – as "a spin on terraforming." Biller also said of the episode, "It definitely has an underlying theme about the interdependence between people and their environment." He additionally implied that he enjoyed writing the episode's friendly interactions between Paris and Kim. (Cinefantastique, Vol. 30, No. 9/10, p. 109)
- According to visual effects supervisor Ronald B. Moore, the teleplay of this episode described the Silver Blood "as mercury." (Cinefantastique, Vol. 30, No. 9/10, p. 111)
- The episode's final draft script was submitted on 4 February 1998. 
- Ken Biller believed that one of the highlights of this episode was its depiction of the Human Kim and Paris socializing with each other, a facet of the episode that Biller enthusiastically referred to as "some good Paris-Kim buddy banter stuff." (Cinefantastique, Vol. 30, No. 9/10, p. 109)
- Ken Biller was positive about what little he saw, during the making of this episode, of director Anson Williams' work on the installment. Biller remarked, "From the dailies anyway, [Williams] did a very nice job." (Cinefantastique, Vol. 30, No. 9/10, p. 109)
- The set of the Demon class planet's surface included a cloudy sky backdrop. (Cinefantastique, Vol. 30, No. 9/10, p. 111)
- For the filming of close-up shots showing Paris' arm reaching into one of the pools of Silver Blood and pulling Kim out of it, Kim's spacesuit was not allowed to be covered in the fluid, as the suits were enormously expensive, so a more elaborate method of creating the sequence was instead used. Ron Moore remembered, "We shot that during second unit [....] We built a big table, and in the table we had an area where we could put the little pool. We had a stand-in for Robbie [McNeill] on the top in a space suit. We had another extra in the arm of a space suit underneath the table reaching up through the hole. So you have [McNeill's stand-in] reaching into the hole, running his hand around, and pulling the other guy up. The hole in the table was covered up, and filled with the goo, and we shot the plate. Once we had the fluid in there, we were dropping rocks to get some surface reaction." These shots would later be augmented with visual effects. (Cinefantastique, Vol. 30, No. 9/10, p. 111)
- According to an uncertain account in the unauthorized reference book Delta Quadrant (p. 241), the physical goo that was used to resemble the Silver Blood was "commercial silver model paint."
- The filming of the scene in which Torres' thumb is recreated by a sample of Silver Blood included a prop thumb on the slide that she and Janeway are using at the time. Ron Moore recalled that this was meant to serve "both as a reference [for visual effects] and to use if we needed to." (Cinefantastique, Vol. 30, No. 9/10, p. 111)
- The Demon class planet's cloudy atmosphere was entirely visualized by Digital Muse, a visual effects provider that was also assigned the task of digitally inserting Voyager into shots newly created for this episode. The company received the CG version of the ship from Foundation Imaging, which had been upgrading the digital model while the other organization had made a transition between being Amblin Imaging and Digital Muse. (Cinefantastique, Vol. 30, No. 9/10, pp. 110 & 111)
- An individual who was instrumental in creating the planet's terrain was visual effects producer Dan Curry. While working on the episode, he noted, "I'm doing Macintosh matte paintings of the terrain." Visualizing this environment made use of numerous photographs that Curry and Ron Moore had taken in Lone Pine, during the production of "Basics, Part I" and "II". Moore later reflected, "We would look through those and select the ones which had a good, basic perspective and a place to put a Voyager." Once this was done, Curry significantly reworked the images. "He would drop out the skies, change the ground," Moore commented. "We didn't figure a Demon planet should have tumble weeds and sage brush, so we took all of that out and made the rocks a little more angular." Sky backgrounds that enhance the matte paintings were temporarily planned to be done by Digital Muse. Ultimately, however, the backgrounds were formed from manipulated examples of footage of the sky backdrop used during production – specifically, photographs that Ron Moore had taken while on the set and frames from first unit photography. "We [...] were able to do split screens to keep them moving a little bit," Moore remarked. (Cinefantastique, Vol. 30, No. 9/10, pp. 110 & 111)
- The visual effects elements for the scene in which Paris drags Kim out of a puddle of the Silver Blood were first sent to Greg Rainoff at Digital Magic, before the shots were turned over to Digital Muse. Ron Moore recollected, "Greg made a precomp where you see the hand go into the fluid. He lined up some of the ripples that we had shot. Digital Muse started with that, and animated the fluid around the arm." The artists involved in creating the sequence were attempting to illustrate the Silver Blood as being akin to mercury, matching its description in the episode's teleplay. Ron Moore himself made the fluid slightly more viscous, giving it a slimy finish. (Cinefantastique, Vol. 30, No. 9/10, p. 111)
- As well as adding Voyager to some of the episode's shots, Digital Muse also recreated the ship's landing struts with CGI. Ron Moore recalled, "We were going to use the shot from 'The 37's' of the strut coming out on the bottom of Voyager. And Muse thought they could do a much better job. It [gave] us a new angle [....] Muse [...] [added] things like the foot, and the little doors." (Cinefantastique, Vol. 30, No. 9/10, pp. 110 & 111)
- Following the creation of the planetary matte paintings, the process of inserting Voyager into them began. However, Ron Moore initially had some reservations about showing the landed Voyager, having had a regretful experience with the creation of such shots in the episode "The 37's", as the scale of Voyager had been incorrectly estimated. He remarked, "In 'Demon' we spent a lot of time to be correct." Firstly, Dan Curry drew small renditions of Voyager, sketches that showed the visual effects artists which perspectives of the ship were most desired. This artwork was then sent to Digital Muse supervisor Bruce Branit. "Then he could take the [digital] models and put them on," Moore remembered, "and send them back to us. By going back and forth a couple of times we got what we wanted. They'd put the ship in and send it back to us with a matte for the ship." (Cinefantastique, Vol. 30, No. 9/10, p. 110)
- It was Ron Moore, rather than either of the visual effects houses, who composited the shots involving the grounded Voyager. This was a rarity for a CGI sequence, though it was far from uncommon for motion control shots to be composited in-house. (Cinefantastique, Vol. 30, No. 9/10, p. 111)
- For the scene wherein Torres' thumb is duplicated by a sample of the Silver Blood, both the fluidic sample in its natural state and the recreation of the Klingon thumb were ultimately done wholly via CGI contributed by Bruce Branit and his co-workers, rather than with the prop thumb that had been in the scene when it had been shot. "Bruce and the Digital Muse people did a marvelous job with that," Ron Moore opined. (Cinefantastique, Vol. 30, No. 9/10, p. 111)
- The final shot of this episode was also visualized by Digital Muse. "Look closely and you'll see characters down there," Ron Moore observed. "We wanted it to be the whole crew, and I felt like that's what [Muse] gave us. I guess they had some characters they had already created for Deep Space Nine. In fact if you look, you'll see some characters that really shouldn't be there. Seven of Nine you just recognize off the bat, but there are a couple more [....] It's the case where computer people worked better." (Cinefantastique, Vol. 30, No. 9/10, p. 111)
Continuity and trivia
- This is the first episode in which Roxann Dawson appears as B'Elanna Torres since she went into labor during the shooting of "The Omega Directive"; subsequently, it is also the first time in season four that Dawson was shown on screen from the neck down (a trick to hide her pregnancy). The only exceptions to this were during "The Killing Game" and "The Killing Game, Part II", during which she is shown (in a holodeck simulation) in the guise of Brigitte – a French resistance fighter who is pregnant with a German officer's child. However, Dawson (in her role of B'Elanna Torres) would wear a uniform jacket designed to help hide her pregnancy, a jacket she had worn since the earlier Season 4 episode "Waking Moments", to the end of the season to keep up the continuity.
- Garrett Wang has claimed that the scene in this episode where Tom Paris asks Harry Kim if he has put on weight was a slight against the male actors on Voyager, as they all had put on weight during the fourth season. Wang claimed that he asked executive producer Brannon Braga why this issue was brought up on the show and Braga allegedly responded "Well, if you and McNeill continue on your eating ways, we'll have to change the name of the show to "Star Trek: Voyager - Pigs in Space"." 
- The idea of crew members having their respiratory (and other) systems altered to require a radically different environment was earlier explored in TAS: "The Ambergris Element". However, the two episodes have significant plot differences.
- This is the first episode which features Voyager operating in "gray mode" to conserve energy. "Gray mode" was seen again in the Season 5 episode "Counterpoint".
- This is the third episode of Voyager to feature the series' title ship landing on the surface of a planet. Other occasions in which the starship Voyager can be seen landing on a planet include Season 2's premiere "The 37's" and finale "Basics, Part I", the Season 6 episode "Dragon's Teeth", and Season 7's "Nightingale".
- Vorik reappears in this episode, having previously appeared in the earlier fourth season episode "Day of Honor".
- This episode takes place ten months and eleven days before the events in the episode "Course: Oblivion" (stardate 52586.3), which features the return of the duplicate crew introduced at the end of this episode.
- This is the third-to-last episode of Star Trek: Voyager's fourth season. Coincidentally, the third-to-last episode of Star Trek: Enterprise's fourth season, aired exactly seven years later, was entitled "Demons".
- Kim mentions that he has fought the Borg ("Scorpion" and "Scorpion, Part II"), helped to defeat the Hirogen ("The Killing Game" and "The Killing Game, Part II"), been transformed into an alien ("Favorite Son") and come back from the dead ("Emanations").
- Neelix tells The Doctor that he knows a Vulcan funeral dirge, a reference to "Tuvix".
- Both Ken Biller and Brannon Braga were pleased with this episode's plot. Biller enthused, "It has a very cool tag to it, a surprise ending [....] It's got some good atmosphere, and some scary stuff, so it should be interesting." Braga opined, "It's a very cool adventure, with lots of cool visuals." (Cinefantastique, Vol. 30, No. 9/10, pp. 109 & 110)
- One person who was not a particularly big fan of this episode was Nick Sagan, a story editor in Voyager's fifth season and co-writer of the script for "Course: Oblivion". 
- This episode achieved a Nielsen rating of 3.8 million homes, and a 6% share.
- Cinefantastique rated this episode 3 out of 4 stars. (Cinefantastique, Vol. 30, No. 9/10, p. 107)
- Star Trek Monthly issue 47, p. 61 scored this episode 3 out of 5 stars.
- The unauthorized reference book Delta Quadrant (p. 244) gives the installment a rating of 4 out of 10.
- Star Trek author Kirsten Beyer once described this as "one of the worst Voyager episodes ever." 
Video and DVD releases
- UK VHS release (two-episode tapes, CIC Video): Volume 4.12, catalog number VHR 4633, 7 December 1998
- As part of the VOY Season 4 DVD collection
Links and references
- Robert Beltran as Commander Chakotay
- Roxann Dawson as Lieutenant B'Elanna Torres
- Robert Duncan McNeill as Lieutenant Tom Paris
- Ethan Phillips as Neelix
- Robert Picardo as The Doctor
- Tim Russ as Lieutenant Commander Tuvok
- Jeri Ryan as Seven of Nine
- Garrett Wang as Ensign Harry Kim
- Carrie Dolin as operations officer
- Tarik Ergin as Ayala
- Sylvester Foster as Timothy Lang
- Jennifer Somers as sciences ensign
- Musso Sparks as sciences officer
- John Tampoya as Kashimuro Nozawa
ability; air; Alpha Quadrant; annular confinement beam; anti-grav thruster; anti-inflammatory; atmospheric gas; assimilation; Astrometrics; atmosphere; attitude control; barbecue; beach umbrella; bedding; bicycle; biobed; bioforming; biomimetic lifeform; blanket; blue alert; boat; Borg; camp; canon; checkout; chemical burn; class Y planet; containment field; corrosion; dead in the water; degree; Demon class; dermalplast; deuterium; dichromate; DNA; dormitory; environment; environmental seal; environmental suit; environmental systems; exercise; expression; eyes; flophouse; fluorescent green; footprint; funny; gag; gas; generator; geophysics; God; gold; gray mode; green; guinea pig; helmet; Hirogen; holodeck; humanoid; hydrogen sulfate; hyperventilation; I'm a doctor, not a...; illumination; Indian; inertial damper; infrared scanner; itch; jackpot; Jirex; joke; Kelvin; kilo; kilometer; Klingon opera; knit; lounge chair; lower atmosphere; lungs; manual control; mark; memory; mess hall; meter; mining; Mister Vulcan; mobile transporter; nacelle; nadion; neck; Neelix' mother; night owl; oxygen; parable; pattern buffer; pedal; personality; pilot; planetoid; plasma; probe; protein; puberty; Puccini; rash; read; red; replicator; resurrection; scanners; Scout; second; Selected Works of Jirex; sense of humor; Silver Blood; singalong; sleep; snoring; sodium chloride; squatter; staff meeting; standard orbit; Starfleet; suffocation; suicide; surface temperature; swim; Talaxian; Talaxian canon; Talaxian rondo; terahertz; thermionic radiation; transporter; Transporter Room 1; turbolift; Type 6 shuttlecraft (unnamed); upper atmosphere; vacation; viscous; volunteer; Vulcan; Vulcan funeral dirge; Vulcan master; warp plasma manifold; weight; weather report; "within arm's reach"; writer
- "Demon" at StarTrek.com, the official Star Trek website
- "Demon" at Memory Beta, the wiki for licensed Star Trek works
- "Demon" at Wikipedia
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