The following contains spoilers for Star Trek: Strange New Worlds Season 2, Episode 2, "Ad Astra per Aspera," now streaming on Paramount+.
The first two episodes of Strange New Worlds Season 2 work like a dual premiere. Spock "borrows" the USS Enterprise to rescue La'an and prevent war with the Klingons. Meanwhile, Captain Pike recruits an Illyrian lawyer to defend his First Officer, Una Chin-Riley, from serious criminal charges related to genetic modification (something also outlawed by the Klingons).
Una is on trial because of Star Trek's greatest villain, Khan Noonien Singh. The Federation outlawed genetic modification because of Khan's crimes; however, as Strange New Worlds Season 2 premiere showed, the Klingon Empire is not a part of the Federation. The episode also showed a return to form for the Klingons, who underwent a redesign for Star Trek: Discovery. However, these Klingons are also different from others seen in the same in-universe era during The Original Series. The 1966 series had a minuscule budget even by the day's standards, meaning the first Klingons were just brown makeup and facial hair. The cranial ridges came later in the movies and successive series. One such series, Enterprise, used genetic modification to "fix" the original Klingons.
How Star Trek Used Genetic Modification to Explain Original Series Klingons
For Star Trek's 30th anniversary, Deep Space Nine used cutting-edge special effects techniques to "visit" an episode of The Original Series. During a scene, Worf and other crew members see TOS Klingons, and he's questioned about their strange looks. Genetic engineering and viral mutation are floated as possible causes, but Worf simply says, "We do not discuss it with outsiders." The moment is played for laughs, but Enterprise executive producer Manny Coto and his writers took this scene and ran with it. They also tied it into an earlier series of episodes from the same season.
Season 4 of Enterprise serialized episodes in mini-arcs, one of which brought in Brent Spiner as Dr. Arik Soong. The story dealt with augments like Khan, who captured a Klingon vessel. The Klingons got samples of these augments' DNA and tried to make their own genetic modifications. The experiment went horribly wrong, creating a super-virus that could've killed every species. Dr. Phlox discovered the solution, a treatment that would blend the human and Klingon DNA. Millions of Klingons and their descendants lost their cranial ridges and developed a more human look.
It's impressive that Coto and company were able to take these disparate plot threads and weave them together. Star Trek fans mostly just suspended their disbelief about the difference in the Klingons' appearance. However, by tying in the genetic augmentation plot, the writers created an in-narrative reason for the disparity. They also answer a question some fans didn't even think to ask: Why haven't the Klingons created their own super-soldiers? The Klingons in Strange New Worlds either weren't affected by this virus or had "cranial reconstruction surgery," mentioned in passing on Enterprise.
Why the Klingons' Appearance on Strange New Worlds Is Noteworthy
Unlike Enterprise, the Strange New Worlds writers didn't mix their Klingon story with the genetic modification storyline. However, their appearance is noteworthy in all senses of the word. First, it marks the first time the classic Star Trek antagonists have appeared in this new series. Second, the Klingons appear as they looked from Star Trek: The Motion Picture onward. The change was due to increased budgets, advancements in prosthetics, and the talent of Michael Westmore. He was the makeup supervisor for the Berman-era of the franchise and brought feature-quality work to the TV series.
The next change to the Klingons' appearance happened for the same reason: movies and money. The Klingons underwent a redesign in the 21st Century. First, for the Kelvin Timeline movies and even more drastically for Star Trek: Discovery. In a way, it's odd that Strange New Worlds seems to be hoping viewers forget about the Discovery redesign. Yet, perhaps by not remarking on it, they're making a statement, nonetheless. One of series creator Gene Roddenberry's mottos for the franchise was "infinite diversity in infinite combinations." Westmore's Klingons were all of a type because he had a budget almost as short as his schedule. There are billions of Klingons, so why shouldn't they have many different looks?
It's possible that Strange New Worlds may pick up Enterprise's storyline about the genetic virus and Klingons without cranial ridges. Perhaps the Klingons fans are most familiar with sharing a heritage with both the "pure" Klingons from Discovery and altered Klingons from Enterprise and TOS. Still, all the trouble it caused in the past is why the Klingons have outlawed genetic modification. Unlike humans, their reminder of its cost is as plain as the ridges (not) on their faces.
Star Trek: Strange New Worlds debuts new episodes Thursdays on Paramount+.