Si Vis Pacem, Para Bellum (episode)
The USS Discovery is tasked with a high priority mission to planet Pahvo and learn the science behind the Klingons' cloaking technology.

Summary

Act One 
The  is under attack from Klingons, calling for help. The  has answered and attempts to keep the Klingon ships (three Birds-of-Prey, a  Destroyer, and two  Battle cruisers) off of the Gagarin. During the battle, they realize the Klingons can't fire while cloaked. After some fire, Captain Gabriel Lorca orders the ship to get in between two of the Birds-of-Prey and the Gagarin, in order to protect her from their fire. Unfortunately, the Gagarin is destroyed and the Discovery is forced to escape via the spore drive.

In engineering, Lieutenant Paul Stamets exits the chamber visibly weak. Oddly, he looks at Cadet Sylvia Tilly, operating the drive, and mistakes her for the captain. When she calls him on it, he gets very irritated and dismisses the mistake.

Lorca has a call with Admiral Terral and questions why his ship is alone in the area. Terral confirms another ambush took place on the  and , straining their defenses. Terral also asks about the invisibility cloaks, and stresses they need a way around it, emphasizing their mission to the planet Pahvo.

On Pahvo, Michael Burnham analyzes the planet. Starfleet wants to use a natural antenna and its unique environment on the planet to detect the cloaked ships. Saru has a fast pace, prompting Burnham and Ash Tyler to encourage him to take in the surroundings. Suddenly, a blue haze starts to coalesce, suggesting an alien presence. Saru makes contact, but receives no verbal response. He suggests it wants them to follow.

On the Sarcophagus, L'Rell returns to meet , greeting him by comparing him to T'Kuvma. Kol dismisses it, and also insists she show value beyond just loyalty. L'Rell offers to interrogate the prisoner, and Kol allows it.

Act Two 
On the planet, the away team follows the blue creature to an enclosed room. Saru is convinced it isn't dangerous. He asks the being if he can analyze the sounds. It coalesces on his hand and disappears in a burst of light. Saru starts to investigate.

L'Rell enters a cell to interrogate the prisoner, which is Admiral Katrina Cornwell. Once alone, she demands Cornwell scream. She then surprises Cornwell by waiting for the guard to leave and then noting that now they can really talk. 

Burnham and Tyler talk a bit during downtime. Tyler expects to go back to his home after the war, and Burnham ponders that she'll go back to prison. Tyler suggests not following through on the mission to keep the war going, and therefore keeping her serving. They kiss.

Tilly has decided to confront Stamets in the mess hall about how he's been acting differently. He tries to order her away, but she stays put. He then reluctantly admits he's sometimes confused about where he is during jumps. He can't admit it to Doctor Hugh Culber since genetic engineering is illegal and it would get him in trouble. 

L'Rell asks Cornwell about how the Federation treats prisoners of war. Cornwell replies they're treated well and eventually returned. L'Rell finally says she wants to defect, saying she's alone now that Kol has perverted T'Kuvma's operation and stripped her of her power. 

Saru comes back to Tyler and Burnham and reports they're still establishing vocabulary. Interestingly, he says the beings are the planet. He's not sure the antenna is their doing, but there will be more to do the next day, so they adjourn. During the night, however, Saru is extremely uncomfortable and gets up, going back to the creatures and asking them to help. The blue haze comes toward him, possessing him and making him relive events of the past. Once they're done, the noise goes away and he's immensely relieved. 

The next day, he meets the away team refreshed, and, oddly, explaining he's already used the antenna to contact the ship. He takes their communicators, breaks them, and says the beings invited them to stay on the planet for good.

Act Three 
Saru leaves to inform the creatures they've accepted the offer. Tyler and Burnham are flabbergasted, and try to come up with a plan.

L'Rell leads Cornwell from the cell to leave the ship undetected. Kol sees them from the other end of a long hallway. Acting quickly, Cornwell and L'Rell pretend that Cornwell has escaped and they fight. L'Rell knocks Cornwell unconscious, but pretends she's dead and takes the body to be disposed of.

Saru comes back to find Tyler alone, and Tyler explains Burnham's absence away. To keep Saru occupied, he asks him about the noise, and Saru seems to suggest nothing matters to him. Tyler says he can't forget what the Klingons did to him, but Saru insists the planet will make them forget. Saru then picks up a green stone and offers it. Tyler puts his hand on it, but then jerks it away – Saru is able to tell he's just been stalling him and leaves immediately. Meanwhile, Burnham has reached the antenna and started using it to call the Discovery. 

L'Rell drags Cornwell to the sarcophagus room. She pauses when she sees that a number of people she knows are now dead. She promises revenge against Kol.

Act Four 
Burnham makes the call but can't see a response. Suddenly, Saru has arrived and throws her back. While they struggle, he tries to destroy the equipment but she makes it to her phaser and knocks him down. She pleads with him, saying he's not himself, but he insists they can't use it. Then, the beings arrive, transporting Tyler there themselves. 

L'Rell informs Kol that Cornwell told her about the power of Discovery, but Kol notes she let the prisoner get away from the room. She still insists she got information and starts to leave. Kol stops her from leaving, saying there will be more POWs. He then starts to anoint her as part of the group, but then turns around and calls her a liar, having known about her actions earlier. He has her taken away.

On the Discovery, they find that their modifications on the planet are gone – only a large EM signal is coming from the planet now. They also find another on a frequency that Klingons use – drawing them there, and the Discovery is the planet's only defense.

Memorable quotes 
"Mr. Rhys, can I trouble you to fire at something?!"
- Gabriel Lorca

"There will be time to grieve. This is not that time."
- Gabriel Lorca, after the destruction of the USS Gagarin

"Our futures look different. You go back to your lake house, and I go back to prison. My sentence was life. This is just temporary."
"Well, maybe we just leave that transmitter alone. You can't go back to prison if we're still at war."
"The needs of the many–"
"Are worth fighting for. Are worth dying for. But so are the needs of the few."
"Or the one?"
- Michael Burnham and Ash Tyler

"I lied to you. And Lieutenant Tyler. I attacked you. I could've killed you."
"You weren't yourself."
"But I was. We are born afraid, we Kelpiens. It's how we survive. As such, my whole life, I have never known a moment without fear. The freedom of it. Not... one... moment. Until Pahvo."
- Saru and Michael Burnham

Log entries 
 "Personal log, Specialist Michael Burnham, Stardate 1308.9. We landed on Pahvo eighteen hours ago. It's a seemingly uninhabited planet, but a unique and, for us, strategic one. Every tree, rock, and blade of grass here vibrates with its own specific tone. Together these combine to form a kind of music, the signature sound of the planet heard everywhere on the surface. The sound is even broadcast into space by a towering crystal structure, a sort of naturally-occurring transmitter. It is Starfleet's plan to modify the electromagnetic frequency of Pahvo's signal and harness it as a form of SONAR that can detect the presence of cloaked Klingon vessels decimating our fleet, make them visible to our sensors, and turn the tide of war in our favor."

Background information

Title and format 
 
 This is also the third live action Star Trek episode without a teaser; the others are  series premiere  and the previous installment to this one, .

Story and script 
 The notion of featuring an away mission to an alien planet was a directive from the television network. "The network wanted them to get off the ship and go to a planet," stated Production Designer Tamara Deverell. 
 The setting of a forest was chosen for this episode because the site was intended to be extremely idyllic. 
 Regarding how Kirsten Beyer devised the episode's plot, Co-Executive Producer Ted Sullivan noted, "This came out of Kirsten Beyer's mind [….] She wanted to explore the idea of peace in the midst of war." ()
 When the DIS writing staff decided to pair up L'Rell and Admiral Cornwell in this episode, they weren't entirely sure if that character pairing would work but they were hopeful it would. ()
 The episode's script gave a detailed description of Saru's sadness at the end of the installment. "It was scripted that Saru had a tear streaming down his face," noted Saru actor Doug Jones. (": The Voyage of Season 1", DIS Season 1 DVD & Blu-ray special features)

Cast 
 Doug Jones endeavored to relate to Saru's euphoric mental state by thinking about it on human terms. "As an actor, personally, to find that space for Saru to play in, uh… it's like, find whatever it is in your life. As people, we have stuff; we have addictions, we have fears, we have childhood issues that we've been dragging into our adult life with us," Jones remarked, with a laugh. "Wouldn't it be nice to be free of them, in an instant?" (": The Voyage of Season 1", DIS Season 1 DVD & Blu-ray special features)
 Culber actor Wilson Cruz was highly impressed by the work that Doug Jones did on this installment. "This should be the episode he picks up an Emmy," Cruz remarked. ()
 Stamets actor Anthony Rapp similarly found this episode remarkably moving emotionally. "This episode made me weep reading it," he admitted. "It's beautiful, the work, especially Doug's work [….] I happened to be on the set when they were shooting one of the scenes so I just watched the monitor, weeping. Just from a take." ()
 Cornwell actress Jayne Brook was pleased that this episode called for her to perform alongside L'Rell actress Mary Chieffo. "I enjoyed it so much," she reminisced. "There's something about L'Rell and Cornwell together [….] And it worked. There was a nice chemistry between those two characters. They really respect each other, these two very different species. And I had a lot of fun with Mary."

Pre-production 
 Tasked with having an episode that would feature an away mission to an alien planet, the DIS writing staff called the production department and asked them to think about feasible ways of accomplishing the task. In approximately ten minutes, Tamara Deverell thought up the idea of including a yurt-like membrane structure, expecting that such a set would be relatively quick and easy to build. After doing a lot of research into many kinds of natural forms and biomimicry, Deverell and her team based the building's design on a repeated mathematical form, then tilted the entire dome so that it wouldn't seem too perfect. The team created silicone membranes that would resemble the planet's alien inhabitants. The whole building was drawn in the 3D computer program Rhino, and the set was thereafter constructed on a soundstage. Another aspect of this episode which was built as a practical element (albeit only partly) was the Pahvan transmitting tower. On the other hand, the Pahvans themselves turned out to be too ethereal to depict using a costume design.

Production 
 The Pahvo scenes were filmed on location at the Hilton Falls and Kelso Conservation Areas in Milton, Ontario, Canada.  The scenes took four very long production days to film. ()
 Even when the shooting company first arrived on location, the working conditions were far from ideal. Ted Sullivan stated, "They were horrible [….] It was hot, it was muggy, and it had just rained a whole bunch, so there was all this standing water [….] There were clouds of mosquitoes. You would breathe, and you'd breathe in mosquitoes. And poor Doug in all of that makeup, he would just take his gloves off and water would pour out of it. It was brutal [….] It was horrible. But […] we needed to go and have an away mission. We needed to go down to [a] planet." ()
 Three different versions of Saru's footwear were used, including regular boots, "sporty" hoof boots, and Saru's heel-less boots. ()
 Doug Jones' Kelpien makeup completely protected him from the mosquitoes. Ted Sullivan humorously commented, "I was begging for them to put me in a Kelpien outfit. I was desperate […] I would even have walked in the hooves just to cover myself." ()
 Jayne Brook noted that the moment when her own character and L'Rell admit being surprised by the other's personality "was so very powerful." Brook also had fun performing Cornwell's subsequent fight with L'Rell. "It was really fun," Brook emphasized. "We had to rehearse quite a lot and then jump right in it, and we did the whole fight." Brook commented that she herself and Mary Chieffo really did "go to town" while shooting the fight scene. ()
 Most of Saru's running was performed by Doug Jones' stand-in and photo double, Bauston Cameron, who did so in full makeup and boots. ()
 It was pouring when the production crew shot the fight scene between Burnham and Saru. Because of the downpour, the ground had to be constantly raked. ()
 Kirsten Beyer was at the location when the Saru-versus-Burnham fight scene went before the cameras. She kept humming well-known combat music from  while watching the fight on the monitor. ()
 During the episode's most emotional scenes, Doug Jones kept crying. However, his prosthetics prevented him from blowing his nose. ()
 After each emotional scene was shot, Director John S. Scott would look at Kirsten Beyer to gauge her reaction. If she was crying, he would then announce, "Okay, we got that, let's move on." () In retrospect, Beyer explained, "Doug (Jones) would just give all of himself, and then we would just sit there and cry on each other for like 20 minutes between setups." 
 Doug Jones enjoyed the scene in which his own character and Michael Burnham make up with each other in the Discoverys sickbay. "[It] was so lovely to play," he noted. () Jones found that accessing the emotional depths required for his part of the scene was reasonably easy. "The tears came naturally [….] Actually, Doug Jones actually cried that day, too," stated Jones. (": The Voyage of Season 1", DIS Season 1 DVD & Blu-ray special features)

Post-production

Visual effects 
 The VFX of this episode included creating the physical design of the Pahvans, augmenting the look of their transmitter, and digitally setting the yurt-like building, even the exterior of which was represented by the appropriate set, in the episode's forest locale. There was ultimately more VFX than Tamara Deverell had intended, however.

Editing 
 According to Tilly actress Mary Wiseman, there was initially a short scene extension at the end of the mess hall scene where her character and Stamets, dining together, discuss how using the spore drive has been affecting Stamets' mental health, though he is adamant about not telling Doctor Culber about that. "Culber walks in, and then, like, Tilly has a conniption, 'cause she immediately cannot keep a secret," Wiseman explained. "That's something that I was playing. It was, like, the first sign I got that maybe I don't have to keep it anymore. I was like, 'Phew, this is the secret." The actress reckoned that this "little scenelet", as she called it, was probably cut for time. ()
 This installment also originally featured a longer "interrogation" scene between L'Rell and Admiral Cornwell. Jayne Brook recalled, "We had a much longer scene in the brig, where I really assess her [using Cornwell's psychology background]. I say to her, 'You don't have the markings of the house of Kol. You don't speak the language, and you haven't killed me yet. So, what's up?" () Brook also referred to the scene as "a great moment." Cornwell's doubting of L'Rell's threats and questioning of who L'Rell was led into the Klingon admitting that she wanted to defect to the Federation.  The excised moment also gave context for the scene in which Cornwell and L'Rell express surprise about the other's personality. However, Brook was ultimately of the opinion that the deleted footage wasn't really necessary. ()

Music and sound 
 When Composer Jeff Russo first began writing music for , this episode was one he knew he would have to compose music for, including a musical theme for the Pahvans. 
 A couple of musical cues from this episode were released in the soundtrack collections Star Trek: Discovery - Season 1, Chapter 1 and Star Trek: Discovery - Season 1, Chapters 1 & 2. The first, called "What's Happening?", is used for the scene where Tyler, Burnham and Saru encounter the Pahvans for the first time, in a forest; the second, "Watch the Stars Fall", accompanies the scene in which Burnham and Tyler have an intimate discussion about their futures and eventually kiss.

Continuity 
 This episode is redolent of some of the other Star Trek television series. Aaron Harberts mused, "If we were to describe this episode, sort of in terms of wine, it has sort of the complex notes of TOS, and sort of several undertones of Next Generation, and always the acidity that is Discovery." (Aaron Harberts' introduction at "Si Vis Pacem, Para Bellum" screening, Millbank Tower, London, UK, ) Ted Sullivan described the episode as "part Star Trek: TNG, a little TOS, a little Voyager." () Noted Kirsten Beyer, "In a lot of ways, it is the first episode of Discovery that is a throwback to an earlier era of Trek, where we've got a planet-based adventure." (": The Voyage of Season 1", DIS Season 1 DVD & Blu-ray special features)
 Similar to how the Discovery maneuvers to a position between a fleet of Klingon warships and a heavily damaged Federation starship, the  does the same thing to protect the  in . Although the  is destroyed in this episode, the Enterprise-C is saved in that installment.
 There is a long-established Star Trek tradition of, as Burnham and Tyler do here, talking about "the needs of the many" versus those of "the few, or the one." These same subjects were previously discussed by: Kirk and Spock twice in ; Kirk and Sarek during a mind meld (in recitation of the latter of those two earlier discussions) as well as again between Kirk and Spock in ; Picard, while requesting Worf donate blood to a dying Romulan in ; Tuvok in a conversation with Janeway in  series finale ; T'Pol during a conversation with Lieutenant Reed in ; and the alternate-reality  in . Although Tuvok (in "Endgame") credits "Ambassador Spock" with having said the phrase, T'Pol established (in "The Council") that it was known well before then, and she also referred to it as "a Vulcan axiom." Those statements account for its usage in this episode, set twenty-nine years before Spock's first on-screen utterance of the phrase in The Wrath of Khan.
 This episode established a romantic relationship between Michael Burnham and Ash Tyler, which follows on from , in which they first meet. The romance also proceeds from the start of a romantic affiliation between Burnham and Tyler in an alternate timeline, included in a time loop in the previous episode, . This is similar to how a married, romantic relationship between Worf and Deanna Troi was depicted in another quantum reality in  before they were shown dating in the prime timeline of the TNG series finale .
 Admiral Cornwell tells L'Rell that the Federation has no death penalty. Assuming this were true, it would indicate that General Order 7 or its death penalty had not yet been implemented.
 Saru's initial telepathic connection with the Pahvans includes some evidently reused footage from  and .
 Like Saru does with a pair of communicators in this episode, Alice 99 crushes a communicator by hand in . ()
 The Pahvans' attempt to peacefully unite the Federation and the Klingon Empire is similar to how, in  (which introduced the Klingons), the Organians attempted to peacefully unite those two heretofore warring organizations. The way the Pahvans' exposure to Saru renders him extraordinarily euphoric is similar to how the Omicron spore in  affect Spock and several other characters in that episode. Both in that regard and in their non-corporeal appearance, the Pahvans are also similar to the Wisps of .

Reception 
 
 Ted Sullivan was delighted with Kirsten Beyer's work on this episode, believing she did an "amazing" job of writing it. "She wrote a beautiful story [….] She takes ideas and turns them on their head, and I think that's what she did so beautifully in this," he commented, "and I think it was unique to look at it through the point of view of Saru, and she, I think, really wrote to the strengths of what Star Trek does best and explore those types of themes." Sullivan was happy, too, with the look of Pahvo, remarking, "It looked great." He also gave credit to Mary Chieffo and Kol actor Kenneth Mitchell for the corridor scene in which Cornwell and L'Rell fight each other. Later, Sullivan again expressed delight with Chieffo's performance, for the scene in which L'Rell has her face painted by Kol. "[She] is heartbreaking. It's amazing," he remarked. ()
  author David Mack was also impressed with Kirsten Beyer's work on this installment. "If the show executes as well as the script… I mean, her script was ama[zing]. Her script actually made me cry; it was beautiful," he enthused. "The ending of the script is heartbreaking. I'm hoping that the production team and the editing team and the post team and everybody, I'm hoping they execute that script on the screen as well as she wrote it on the page. If they do their jobs as well as she did hers, there won't be a dry eye in the house on 108." 
 The scene in which Saru, Burnham and Tyler establish first contact with the Pahvans debuted on .
 By the time this episode was due to be released, most people were of the opinion that it was about time DIS had an episode in which the Discovery visited an alien planet. ()
 In the United Kingdom, this episode debuted with a private screening in London on , at which the episode was introduced by Aaron Harberts. Opening the proceedings with a speech about this installment and Kirsten Beyer's writing of it, he commented, "What's exciting about this episode is the tenderness with which she treats the peace." The preview screening was immediately followed by a Q&A with guests Sonequa Martin-Green, Jason Isaacs, Shazad Latif, and Aaron Harberts.
 After Trek host and Star Trek fan Matt Mira was wowed by this episode, glad that it included an away mission and believing Kirsten Beyer had done a "fantastic job" by writing it. "It was such a Star Trek-ian episode," he remarked. () Mira also enthused that the scene which shows a landing party from Discovery meet the Pahvans was "very exciting." ()
 Some footage from this installment was evidently reused in the next episode, .

Production history 
 : Title publicly revealed 
 : Premiere airdate on CBS All Access
 : International release date (outside Canada and the USA)
 : US broadcast premiere on the CBS Television Network

Video and DVD releases 
As part of the DIS Season 1 DVD collection
As part of the DIS Season 1 Blu-ray collection

Links and references

Starring 
 Sonequa Martin-Green as Michael Burnham
 Doug Jones as Saru
 Shazad Latif as 
 Anthony Rapp as Paul Stamets
 Mary Wiseman as Sylvia Tilly
and 
 Jason Isaacs as

Guest starring 
 Jayne Brook as Katrina Cornwell
 Mary Chieffo as L'Rell
 Wilson Cruz as Hugh Culber
 Kenneth Mitchell as

Co-starring 
 Michael Boisvert as Kovil 
 Conrad Coates as Admiral Terral
 Emily Coutts as Keyla Detmer
 Anthony Grant as Klingon Communications Officer
 Julianne Grossman as Discovery Computer
 Patrick Kwok-Choon as Rhys
 Sara Mitich as Airiam
 Oyin Oladejo as Joann Owosekun
 Ronnie Rowe Jr. as Bryce
 Tyler Evan Webb as Klingon Guard

Uncredited co-stars 
 Andrea Gallo as Alien sciences crewmember
 Graeme Guthrie
 Marco Perretta as a Medical Officer
 Michelle Yeoh as Philippa Georgiou (archive footage)
 Unknown performers as 
 Grafk
 Silrek
 Torath
 Medical crewmember
 Gagarin officer

Stunt doubles 
 Nicole Dickinson as stunt double for Mary Chieffo
 Unknown performer as stunt double for Jayne Brook

Stand-ins 
 Stacy-Ann Buchanan – stand-in for Sonequa Martin-Green
 Bauston Cameron – photo double and stand-in for Doug Jones

References 
acceleration; apex predator; armada; auditory receptor; beach; Cancri IV; career; cloaking device; communicator; crystal; daydream; death penalty; DNA; electromagnetism; ; evasive pattern; falling star; first contact; first contact protocol; first contact specialist; freedom; ; General Order One; genetic manipulation; hangar; honor; ; House of Kor; invisibility screen; Kahless; Kelpien; kilometer; kilometers per hour; Klingon battle cruiser; ; Klingon destroyer; Lake Shasta; mek'leth; ; Pahvan; Pahvan transmitter; Pahvo; protein ration; radio silence; RFM modulator portapack; sailboat; Sarcophagus; senior officer; sensory ability; sentient being; ; ; signal inhibitor; SONAR; specialist; symbiosis; synthetic protein ration; teactile receptor; ; threat ganglia; torture; T'Kuvma; ; tribble; tricorder; trout; UFP Serial Code; universal translator; visual receptor; vocabulary; warp-capable

External links 
 
 
 
 
 

de:Si Vis Pacem, Para Bellum
es:Si Vis Pacem, Para Bellum
fr:Si Vis Pacem, Para Bellum (épisode)
pl:Si Vis Pacem, Para Bellum
DIS episodes