(written from a Production point of view)
Lorca plans to move forward with a coup against the Emperor, propelling Burnham to make a quick decision to save not only herself, but the USS Discovery.
Act One Edit
In the mirror universe, aboard the Terran emperor's flagship, the ISS Charon, Gabriel Lorca frees his followers from a chamber filled with agony booths, including his loyal partner Commander Ellen Landry. Lorca and his men seek out Paul Stamets and use his bioweapon to start killing the Emperor's crew.
The Emperor is informed of the casualties of her crew. Michael Burnham advises her to allow her to contact USS Discovery again, but the Emperor does not agree and decides to imprison her in the brig. Burnham is forced to flee and escapes through a small hole in the wall.
Aboard the Charon, Lorca taunts Georgiou, and invites her crew to join his rebellion to preserve the empire. Georgiou identifies his location in the main labs, and leads her troops to "take the fight to him."
Act Two Edit
Emperor Georgiou's forces come head to head with those of Lorca, after which she alone escapes being killed using an emergency transport system. Lorca orders Stamets to kill the emergency transport system and they secure the throne room.
Burnham accesses the Charon's communications system to contact the Discovery, warning them that Lorca is in fact from the mirror universe. The crew convey the importance of bringing down the containment field around the energy orb powering the palace ship. Burnham promises to take down the containment field.
Entering the throne room, Lorca's confidence that fate had brought him to this point grows, before killing the mirror universe Stamets. Landry is informed of the ship-to-ship transmission.
Act Three Edit
Lorca tracks Burnham to level 3, and attempts to convince her to join him in his rebellion against the emperor by describing his past with the Burnham from his universe. Landry attempts to capture her while Lorca is distracting her, only to find Burnham had rerouted the communications feed masking her location.
The emperor, too, is thinking back to her relationship with the mirror Burnham, when Commander Burnham finds her. Burnham explains the parallels between her betrayal of her Georgiou, and the mirror Burnham's betrayal of the emperor. Together, the two discuss the plan to defeat Lorca.
Aboard Discovery, the crew discuss options to destroy the energy orb, but the only option seems as though it will also result in the Discovery's destruction. Saru rallies the senior officers, indicating he does not sense death in their future and that they will defeat this "no-win scenario."
In the throne room aboard the Charon, Landry reports to Lorca that the emperor's crew has either been killed or joined their movement. Lorca's guards capture and bring Burnham and Georgiou to Lorca. Burnham agrees to offer Georgiou and herself, her mind only, in exchange for letting Discovery return to their universe.
Act Four Edit
Tilly and Stamets discover a way to escape destruction, if they ride the mycelial explosion in conjunction with the warp drive.
Discovery receives a message from the Charon and drops out of warp, then receives a hail from Lorca. Burnham sends a coded indicator to attack, and the Discovery launches its attack, kicking off a hand-to-hand battle between Lorca and Georgiou, and Burnham and Landry. Georgiou eventually defeats Lorca by stabbing him through the heart with her sword, before kicking him through a force field out into space to be vaporized in the ship's mycelial sun.
Lorca defeated, Georgiou prepares to buy Burnham time by fighting off Lorca's remaining followers. Burnham grabs Georgiou, pulling her into the transporter beam and bringing her to Discovery.
Discovery attacks the Charon's energy orb – setting off the mycelial shockwave, which Discovery combines with its strategy to jump to warp to ride back to the prime universe. Stamets struggles to navigate the recovering mycelial network until he can remember Hugh's advice.
Discovery seeks to confirm the date and location they've returned to, with no response from Starfleet. Stamets finds that they've returned nine months ahead of the point that they left, to which Saru immediately asks Rhys to update their map of the war effort. The map reveals a major expansion of Klingon territory, with Starfleet having all but lost.
Memorable quotes Edit
"It is well known that my species has the ability to sense the coming of death. I do not sense it today. I may not have all the answers; however, I do know that I am surrounded by a team I trust. The finest a captain could ever hope to command. Lorca abused our idealism. And make no mistake, Discovery is no longer Lorca's. She is ours. And today will be her maiden voyage. We have a duty to perform, and we will not accept a no-win scenario. You have your orders. On your way."
- - Saru
"What the hell are they doing?... Is the containment field up?!"
Log entries Edit
- "Captain's log, stardate 1834.2. Acting Captain Saru recording. We are en route to the Terran flagship, having been summoned by Specialist Burnham. Discovery's spore drive is operational again, thanks to the full recovery of our navigator, Lieutenant Stamets. Yet, despite his best efforts, the lieutenant was unable to save Discovery's mycelium crop. His fear is that his Terran counterpart has already contaminated the network, and if so, the results could be catastrophic."
Background information Edit
- After Trek "Episode 12" discusses the making of, and events in, this episode.
- "What's past is prologue" is a phrase from Act 2, Scene I of William Shakespeare's The Tempest. It also inspired the title of the Star Trek: Deep Space Nine episode "Past Prologue" as well as Jake Sisko's story "Past Prologue" in DS9: "The Ascent" and the Pocket TOS novel Past Prologue.
- Shazad Latif (Ash Tyler) does not appear in this episode.
- Counting Ash Tyler as a Klingon character, this is the first Discovery episode that does not feature any Klingon.
- It's revealed the mirror Gabriel Lorca arrived in the prime universe via a transporter accident the same way Kirk, McCoy, Scott, and Uhura entered the mirror universe in 2267; in Lorca's case, it was while beaming up to ISS Buran during an ion storm.
- This is third episode of the series without a teaser after "Magic to Make the Sanest Man Go Mad" and "Si Vis Pacem, Para Bellum".
- This episode marks the first time a main character who is a commanding officer has been written out of their series of origin.
- The mirror universe Michael Burnham's serial number, SHN4790 4600CS, mostly mirrors the prime universe Burnham's Starfleet serial number: SC0064-0974SHN.
- The visual effect of the inter-universe mycelial travel bears a certain resemblance to the Slipstream travel in the TV show Gene Roddenberry's Andromeda - the animation as well as the "Shake, Rattle 'n' Roll". The score of that scene (classical-style aria) also bears a similarity to a similar scene (return to the prime universe after a longer stay in another universe) in the Andromeda episode "The Heart of The Journey (Part 1)".
Production history Edit
- 13 December 2017: Title publicly revealed 
- 28 January 2018: Premiere airdate on CBS All Access
- 29 January 2018: International release date (outside Canada and the USA)
Links and references Edit
- Sonequa Martin-Green as Michael Burnham
- Doug Jones as Saru
- Shazad Latif as Ash Tyler
- Anthony Rapp as Paul Stamets / Paul Stamets (mirror)
- Mary Wiseman as Sylvia Tilly
Special guest star Edit
Guest starring Edit
- Emily Coutts as Keyla Detmer
- Jeremy Crittenden as Lord Eling
- Patrick Kwok-Choon as Rhys
- Sara Mitich as Airiam
- Oyin Oladejo as Joann Owosekun / Joann Owosekun (mirror)
- Ronnie Rowe Jr. as Bryce
Uncredited co-stars Edit
- Bart Badzioch as ISS Charon officer
- Mustafa Bulut as ISS Charon officer
- Wilson Cruz as Hugh Culber (archive footage)
- Phi Huynh as ISS Charon officer
- Jonathan McGuire as ISS Charon officer
- Joseph Racki as ISS Charon officer
- Julie St-Louis as ISS Charon officer
Stunt doubles Edit
- Christine Ebadi as stunt double for Rekha Sharma
- Nilo Ghajar as stunt double for Sonequa Martin-Green
- Geoff Meech as stunt double for Jason Isaacs
- Melanie Phan as stunt double for Michelle Yeoh
agony booth; Alpha Quadrant; ambush; battalion; Battle of the Binary Stars; bioweapon; black alert; border; brig; Buran, ISS; carrier address; Charon, ISS; clearing; containment field; coup d'état; emergency transport; emperor; energy dispersal; flash grenade; forest; Georgiou, Philippa; hack; Harlak; hypergravity; ion storm; life sign; lord; magnetic field; mirror universe; multiverse; mycelial energy; mycelial network; mycelial shockwave; mycelial spore; mycelium; nanometer; noose; no-win scenario; parallel universe; pathway; photon torpedo; physics; pillow talk; poetic justice; poetry; poison; Priors World; race; rebellion; revolution; sanctuary; senior officer; Starbase 46; subatomic analysis; super-mycelial reactor; superstructure; sword; terahertz; throne room; torture; transporter signature; United Federation of Planets; vaporize setting
Rhys' tactical star chart Edit
- "What's Past Is Prologue" at StarTrek.com, the official Star Trek website
- "What's Past Is Prologue" at Memory Beta, the wiki for licensed Star Trek works
- "Discovering the Prologue" at MissionLogPodcast.com, a Roddenberry Star Trek podcast
|Mirror universe-related episodes|
|ENT: "In a Mirror, Darkly" • "In a Mirror, Darkly, Part II"|
|DIS: "Into the Forest I Go" • "Despite Yourself" • "The Wolf Inside" • "Vaulting Ambition" • "What's Past Is Prologue"|
|TOS: "Mirror, Mirror" • "The Tholian Web"|
|DS9: "Crossover" • "Through the Looking Glass" • "Shattered Mirror" • "Resurrection" • "The Emperor's New Cloak"|
| Previous episode:|
| Star Trek: Discovery|
| Next episode:|
"The War Without, The War Within"