Discovery embarks on its mission to cross the galactic barrier and make contact with Species 10-C. Meanwhile, Book and Tarka gather supplies for their own journey through the barrier, revisiting Tarka's past along the way.
Tropes:
- Ambiguously Evil: Still the case with 10-C. Even though the new DMA is orders of magnitude more dangerous, it's not clear if this is a deliberate reaction to an attack or simply them reinforcing it after it was previously disabled.
- The Bus Came Back: Ensign Adira Tal is recalled to duty on the Discovery and remains there throughout the remaining episodes of the season. Gray does not return with them, though no indication is given that this has any significance.
- Came Back Strong: The DMA was not only replaced, its power source was increased nearly ten times, turning what would have been a week of mining into a mere 12 hours.
- Contrived Coincidence: The exact thing Tarka needs to reinforce Book's ship against the galactic barrier also happens to be something he stashed for a completely unrelated reason in an old hideout.
- Closest Thing We Got: Since the mission timetable is moved up, Ni'Var's representative can't make it and T'Rina joins the mission instead, reasoning that Ni'Var needs a representative, even if it has to be its president.
- Exact Time to Failure: Averted. Owosekun counts down until their shields fail as Discovery heads into one of the bubbles of stable space. They make it to the bubble with six seconds to spare.
- From Bad to Worse: The more powerful DMA not only cuts down the time Starfleet has to make contact with 10-C, but it also has the potential to cause even more damage.
- Garden of Eden: While prisoners of the Emerald Chain, Oros and Tarka secretly worked on an interdimensional transporter that could take them to “Kayalise,” a mythical parallel universe meant to be a paradise. Tarka managed to escape and hid in a nearby cave, and is convinced Oros made it because he disappeared one day after a massive energy surge, with no record of his existence one way or another after that incident.
- Flashback: There are flashbacks to Tarka's time as a prisoner of the Emerald Chain, showing how he met his friend Oros and bonded with him.
- The Lost Lenore: Oros serves as this to Tarka. While nothing is made explicit, their body language indicates a bond of at least Heterosexual Life-Partners,
if not more. - Negative Space Wedgie: The galactic barrier looks like a large tear filled with dangerous particles that threaten to tear apart Discovery in minutes, even with their shields reinforced with antimatter. Discovery is able to take refuge inside bubbles of stable space, but has no way to control where the bubbles form or their movement, making it a close-call to ride them through.
- No Warping Zone: Since the mycelial network can't pass through the Galactic Barrier, Discovery can't spore-jump through it and must therefore take the slow route.
- Shout-Out: To Gilligan's Island, of all things, when Kovich refers to the First Contact mission as a "three-hour tour". Saru doesn't understand the reference.
- Starfish Aliens: Discussed during the pre-mission briefing. The Federation has zero frame of reference in dealing with 10-C, who could very well not be humanoid or even communicate verbally. Kovich brings on a xeno-linguist just in case standard universal translators prove useless.
