(written from a Production point of view)
Ephraim, a humble tardigrade, is flying through the mycelial network when an unexpected encounter takes her on a bewildering adventure through space.
A movie filmed in black and white by the name of The Tardigrade in Space appears on the screen, presented by Starfleet Science. It depicts a journey through the mycelial network, and the narrator opens the movie by saying "space, the final frontier...", going on to talk about how the galaxy is filled with flora and fauna, some of which were both deadly and docile. The image on the screen shows a picture of a deadly M-113 creature and contrasts it with a docile tardigrade named Ephraim. He continues, stating that Ephraim uses the mycelial network as a "super-warp highway," allowing her to travel vast distances throughout the galaxy, hoping to find a place to take her precious cargo: her eggs. The narrator states that tardigrade eggs can lie dormant for years, and so it's important for the mother tardigrade to find a safe spot for them. She begins digging into a meteoroid, hoping to bury them in there. But just then, her antennae start to sense something she thinks might be a predator.
Just then, the film instantly transitions to color, and the USS Enterprise drops out of warp, smashing into the meteoroid near the deflector dish. Ephraim jumps off in time, flying around checking out the massive starship. She starts scratching with her claws, trying to dig into the hull, then she sets down close to a window where sickbay is. On the interior, Captain Kirk and Doctor McCoy are talking with Khan. While on the exterior, the tardigrade is scratching at the sickbay window trying to get inside. Just then, Dot, a DOT-7 robot emerges on the hull from a circular hatch, and sees the alien intruder and immediately goes after her. He zaps her with some sort of electric shock, repelling her away from the hull. He then returns through the hatch to the interior of the ship. The tardigrade then follows, slamming into the robot and causing them to go hurtling toward laundry baskets with Starfleet uniforms in them, knocking them out and causing them to be covered by a big ball of shirts.
After emerging from the shirts, Dot is wearing a redshirt and prepares to shock Ephraim again. The tardigrade takes off running. She is then accidentally sucked into what appeared to be a life support tube, and she next finds herself near the warp core in engineering. She crawls under the fenced off area and emerges in the core. There she lays her eggs. She is then pulled out of the warp core by Dot, and she narrowly escapes getting jettisoned into space. The chase continues, she enters a Jefferies tube full of tribbles and they all fall out, slowing the robot's pursuit down a bit. She next hides somewhere near a corridor, where Hikaru Sulu is threatening to cut other crewmembers with his sword. However, Dot locates her in a tank and then jettisons her into space. Dot closes the door and tells her to "live long and prosper". The Enterprise then goes to warp.
But the tardigrade enters the mycelial network, easily keeping up with the ship for many years. She encounters a giant green hand, planet killer, Tholian web, a giant Abraham Lincoln, and the USS Reliant. She then lands on the hull of the ship and looks inside to see her eggs. Just then, she senses something again. This time, it is Kruge's Bird-of-Prey de-cloaking and attacking the Enterprise. The disruptor blasts cause a massive hull breach, which allows the tardigrade access to the ship. Meanwhile inside, Dot is using his fire hose-like arm to put out the fire, and then he notices the tardigrade running by. He begins his pursuit.
While in the warp core, the mother tardigrade is excitedly reunited with her eggs, only to be shoved away from them by the robot. He violently slams her against the floor plating over and over again, before spinning her around and throwing her. The tardigrade grabs a tool to use as a weapon and begins fighting the robot. When debris starts to fall near the eggs, the tardigrade becomes nervous, and the robot shocks her again, then knocks her into an airlock and blows her into space. The robot goes back to putting out fires when it suddenly notices one of the eggs. It begins scanning the area and it finds other eggs. The computer voice states that the self-destruct sequence is engaging, and explosions begin to occur throughout the ship. As the explosions grow closer to Dot, the robot begins to scream as if in a panic.
While on the exterior of the ship, the mother tardigrade takes flight back toward the ship, but just as she approaches the large spacecraft, it explodes. The force of the explosion sends the tardigrade backward, and debris flies everywhere. The tardigrade seemed to be knocked unconscious, but comes to very quickly, in time to see what was left of the ship come crashing down on the Genesis Planet. She sees the robot Dot floating in the vacuum of space and angrily attacks it. But the robot shakes its head "no," and opens up its body and reveals the baby tardigrades inside. The mother is very happy to see them. The narrator closes the film by saying that she finally found peace, and he goes on to say that "we can't help but wonder what adventures await as our new family goes boldly where no one has gone before!" They then fly off into the mycelial network and the movie ends.
- The title of this episode was first revealed in a trailer released on 20 July 2019 at San Diego Comic-Con. The trailer (and official announcements made at the same time) misspelled "Ephraim" as "Ephaim".  
- The release date was announced on 5 October 2019 at New York Comic-Con. 
- Michael Giacchino confirmed on Twitter that he was directing this episode, and that it will be animated. 
- Alex Kurtzman stated that this episode and "The Girl Who Made the Stars" are both "tied to Discovery, but in interesting and surprising ways." 
- In the first trailer for this episode, the title character Dot appeared with blue markings instead of red ones, like the DOT-7s previously seen in Star Trek: Discovery.
- This is the first appearance of the USS Enterprise in animated form since "The Counter-Clock Incident", the last episode of Star Trek: The Animated Series, in 1974. It is also the first time a refit Constitution-class has been depicted in animation. In fact, this short, along with "The Girl Who Made the Stars", which premiered at the same time as this episode, are the first animated episodes or film in the Star Trek franchise in over 45 years.
- Khan is seen in animated form for the first time. Khan premiered in "Space Seed" and was last seen in Star Trek II: The Wrath of Khan, while his alternate reality counterpart was in Star Trek Into Darkness.
- This episode also includes the first appearance of the prime universe's James T. Kirk and Leonard McCoy since "Trials and Tribble-ations", excepting only the photograph seen in Star Trek Beyond. It is also the first appearance of the prime universe Hikaru Sulu since "Flashback", excepting the same photograph.
- When Ephraim first encounters the Enterprise, she looks into a sickbay window and witnesses a conversation between Captain James T. Kirk, Khan Noonien Singh, and (silent) Leonard McCoy, as previously seen in "Space Seed". After she lays her eggs in the Enterprise's warp core, she encounters tribbles, as seen in "The Trouble with Tribbles". Immediately afterwards, Ephraim and Dot are adjacent to a corridor in which Hikaru Sulu is seen and heard shirtless and with a rapier, as in his polywater intoxication seen in "The Naked Time". These events, which appear in close succession in the episode, occur at different times on the Enterprise, suggesting either that the episode's events are compressed for dramatic purposes or that tardigrades experience time in a non-linear fashion.
- Similarly, after Dot ejects Ephraim from an Enterprise airlock, Ephraim witnesses, in quick succession, the giant green hand of "Apollo", ("Who Mourns for Adonais?") the "planet killer", ("The Doomsday Machine") the Tholian web, ("The Tholian Web") the Excalbian recreation of Abraham Lincoln, ("The Savage Curtain") the USS Reliant attacking the refit Enterprise, (Star Trek II: The Wrath of Khan) and then the attack by Kruge's Bird-of-Prey and subsequent self-destruction of the Enterprise. (Star Trek III: The Search for Spock) Again, events occurring at different times, even decades apart, are depicted as following swiftly after each other.
- In the depictions of the Enterprise set during Kirk's five-year mission, the ship is externally depicted in the retcon configuration seen in Discovery, though the interior matches the original depictions more. In the depictions of the refit-configuration from the films, the ship is incorrectly labeled "NCC-1701-A", an error Giacchino acknowledged in a tweet, citing a difficult schedule.  Its hull markings don't match the markings from the physical model, and the upper saucer's detail is also rotated 45 degrees counterclockwise. The battle damage from The Wrath of Khan is absent from the final depiction of the ship, and the final battle over Genesis causes significantly more damage than it did in the film, though since most of the episode is more or less from Ephraim's POV, or at least a stylized and compressed depiction of events spread over twenty years, these dependencies can be attributed to the tardigrade's experience of these events or the differences in the overall art style.
Links and references
- William Shatner as James T. Kirk (archive audio recording)
- George Takei as Hikaru Sulu (archive audio recording)
- Ricardo Montalban as Khan Noonien Singh (archive audio recording)
- Unknown performers as
adventure; black and white; blood; Bounty, HMS; captain; doctor; DOT-7; egg; Enterprise, USS; Excalbian; green hand; Genesis; Human (Augment); highway; Jefferies tube; Klingon Bird-of-Prey; lieutenant; life support canister; movie; peace; planet killer; Reliant, USS; self-destruct; sickbay; Starbase 12; Starfleet; Starfleet Science; Starfleet uniform; sword; tardigrade; Tardigrade in Space, The; Tholian web; Tholian ship; tribble; warp core
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"The Girl Who Made the Stars"