While Dr. Phlox is dictating a letter to his colleague Dr. Lucas, Enterprise is called in to save an alien race from extinction.
- Aborted Arc: Phlox and Crewman Cutler flirt with each other this episode, but nothing comes of it in later episodes. Her actress, Kellie Waymire, would later die during the filming of Season 3, but Cutler had already stopped appearing after Season 1.
- Alien Non-Interference Clause: At first subverted; since the ship encountered was explicitly looking for help and the M'klexa and Ferengi have already dropped by, even T'Pol thinks it no longer applies, so an away team visits the planet to learn more about the medical crisis. After discovering its cause and a pitch by Phlox that they shouldn't interfere, Archer eventually decides against helping the Valakians since "we didn't come out here to play God." Notably, they couldn't have done this in any other series of the show, since the Prime Directive has been established to have an exemption for people who actually ask for help.
- Appeal to Nature: Doctor Phlox argues against curing a disease affecting the Valakians on grounds that the existence of the Valakian species is holding back the evolution of the Menk species on the same planet. He argues to Captain Archer that they should "let nature take its course". For icing on the cake, Archer's closing monologue in effect claims this incident as the origin of the Prime Directive.
- Artistic License Biology:
- Evolution leads species to inadvertent extinction all the time, usually from something like overspecialization, such as a single species parasite being out of luck if that species itself goes extinct. But the idea of a straight up genetic disease, somehow treatable with antibodies yet interfering with protein production to the point of death, spreading enough to doom an entire species, is simply nonsense.
- Phlox believes, based on scant and untested evidence from less than 2 days of information gathering and genetic profiling, that the Menk will someday be the dominant sentient species on the planet if the Valakians go extinct. But assuming future evolution from current trends, and making a medical conclusion based on that, is extremely arrogant and shortsighted. In addition, evolution has competition as a large component; far from 'holding them back', their relationship with the Valakians could in fact be what is driving the Menk to become more intellectually sophisticated, and Phlox is in fact dooming both species.
- Conflation of theory and Scientific Theory on the topic of evolution, but reversed from the usual misconception that evolution is 'only' a theory; Archer (accurately) says that the conclusions of Phlox concerning the relationship of the Valakians and Menk are only a theory, which Phlox in his response dismisses by deferring to the Theory of Evolution. This is a non sequitur, since Archer was clearly using the term generically to refer to what in scientific parlance would be a hypothesis, something which needs testing and is certainly not a final conclusion.
- Blue-and-Orange Morality: Lampshaded by Phlox to Cutler, but the main dilemma is a fairly straightforward medical ethics clash between human and Denobulan perspectives.
- Call-Forward: The Ferengi are briefly mentioned as having visited the planet, though no one recognizes their name.
- Culture Clash: Phlox is a bit wary of this happening with Cutler.
- Exotic Extended Marriage: Phlox reveals that this is standard on Denobula. He has three wives, each of whom have two husbands in addition to him.
- Friends with Benefits: Cutler has no objection to an interspecies fling with a married man, though perhaps she has already learned as viewers do in a later episode that Phlox (and Denobulans at large, presumably) has no objections to doing so either when his wife, Feezal, propositions Commander Tucker while helping them install a quantum microscope she delivered to Enterprise, which Phlox encourages him to accept. While Phlox understands Trip's hesitance to oblige, he and his wife are nonetheless amused with humanity's sexual norms.
- I Can't Believe I'm Saying This:
Captain Archer: I never thought I'd say this, but I'm beginning to understand how the Vulcans must have felt.
- Regarding the dilemma of whether and how to teach a species to build warp engines, and the irony of facing it despite disliking perceived Vulcan foot dragging on that very same topic.
- Offscreen Inertia: Since this episode is the first and last time we see these species, it is commonly assumed that the decision by Archer to not offer a cure at the end means that the Valakians were doomed to extinction. However, this is all being filed in his reports to Starfleet, which the Vulcans read. Archer himself says that they may still figure it out for themselves with the treatment information he does give them buying them at least a decade to do so, and Phlox earlier said that the timeframe for complete collapse was a couple centuries. Archer's decision at that moment is therefore by no means the final word.