It should not come as a surprise that I am a long-time fan of the Star Trek franchise, having watched the various series with some regularity since 1987 and the debut of Star Trek: The Next Generation. That watching has most recently been through streaming video services rather than catching the various series and movies in syndication and theaters, and that streaming video watching turned not long ago to Star Trek: Voyager. One of the less-popular Star Trek properties, it ran from 1995 to 2001 (per IMDB.com) and follows Kathryn Janeway and the crew of the eponymous ship through abduction into the Delta Quadrant and travel back to the Federation space from which they came. Suffering the effects of franchise fatigue and, perhaps, a reaction to the darker atmospherics of Star Trek: Deep Space Nine, Voyager languished on minor networks through its initial run and now attracts attention primarily as a negative example (if not so much as Star Trek: Enterprise). Its deployment of medievalism in the early episode "Heroes and Demons" is one encapsulation of the phenomenon; it serves in some ways to underscore its utility as an image of what not to do.
In the episode, the eponymous starship comes across an unusual photonic phenomenon and stops to investigate it. Meanwhile, one of the senior bridge crew, Ensign Harry Kim, is taking recreation in the holodeck, the illusory suite that will replicate a number of experiences for its users. When he is summoned to duty and does not appear, his crewmates begin to search for him; they find that he has vanished amid his holodeck program, an adaptation of an adaptation of Beowulf. In the event, the photonic phenomenon encountered by Voyager is a home for photonic life forms who interact uncomfortably with the holographic constructions of the holodeck; those life forms had used the cover of Grendel in the holodeck program to abduct ship's crew in retaliation for the (admittedly inadvertent) abduction of their own from the phenomenon by the starship's investigation. The ship's holographic doctor is able to carry out what amounts to a prisoner exchange, returning the abducted photonic life forms and retrieving the stolen ship's crew.
Many avenues of critique of the episode and the series of which it is part present themselves, and they are well worth exploring. That most relevant to the work of the Society, however, attends to how the episode presents the purported milieu of Beowulf. That there will be changes to the work for its representation is understandable and even necessary; the original work, cast in Anglo-Saxon verse, would necessarily need alteration to suit the in-milieu new medium of the holodeck (particularly with its interactive elements), as well as the narrative medium of the television series. Too, the program Kim runs is explicitly labeled as "based on" the Anglo-Saxon epic; it is overtly a derivation and deviation within the milieu, rather than a re-creation of the poem. Some "inaccuracies" in the presentation are therefore to be expected and to be "forgiven," if such changes are indeed to be regarded as erroneous (and there are good arguments why they should be, to be sure, such as Helen Young's "Who Cares about Historical Accuracy? I Do").
That some changes are to be expected and set aside as necessary to translations across media does not mean that all of the present changes are good, however. The insertion of the character Freya into the story serves as an example of a less-than-ideal alteration. While there are certainly accounts of shieldmaidens in legends and contemporary "historical" reports (which are not always accurate in the sense that we commonly understand accuracy), and there were certainly warriors who happened to be women among the people of the time and place depicted in Beowulf, the replacement of the unnamed coast-warden--who is explicitly labeled in masculine terms (and who is not unaccompanied, having retainers to order to hold Beowulf's ship against his return [ll. 293-300])--with Freya comes across as an imposition of a female character for the express purpose of having a female character in a more active role than the poem presents (much like the "enhancement" of Arwen's role in Jackson's Lord of the Rings movies or the insertion of Tauriel into his Hobbit films). That she seemingly exists as a love interest whose death inspires heroism from the male protagonist reinforces the impression of Freya as a sop to particular interests, an inclusion made to fill a particular diversity slot rather than as an important part of an amended story. The name, as well, betrays a sense of "oh, this sounds medieval and female; it fits a hole we need." While the overtones of the name--it is one of a goddess of love and war, among others--are perhaps appropriate to the character's function, the relative ineptness of the character herself suggests that the name was chosen for ease of speaking rather than authenticity of depiction. As a change to the source-text, is it one one that responds to prevailing misconceptions about what it true and what needs "fixing" in one medieval culture, making it a model of what to avoid in medievalism.
Problems inhere in matters that are less "change" and more "typical presentation," as well. The problem of the "monochrome Middle Ages" that Young decries in "Who Cares about Historical Accuracy? I Do" and elsewhere is painfully present in the episode (although the argument could easily be made that the relative remoteness of Heorot and the poem-stated identification of the Danes sworn to Hroðgar could make for homogeneity in the population). Aside from the Voyager crew who enter the holodeck and the photonic life form that is regarded as villainous, the characters in the program are white, almost exclusively male, and bearded (with little-kept beards)--fitting a common and ultimately inaccurate image of the medieval. The architecture of Heorot in the episode accords little with what is known of mead-hall building, but it fits the half-timbered construction associated with "lesser" buildings in common understandings of the medieval--a style of building common to later periods than that discussed in Beowulf. As with the half-hearted inclusion of Freya, the depiction of Heorot and its inhabitants seems more calculated to accord with generic medieval ideas than with the best information available at the time about how the early medievals lived. It is something that is not to be expected from the demonstrably scholarly Starfleet personnel depicted across the Star Trek franchise, and it is not something that should be taken as a model of medievalist storytelling.
There are other problems to be found with "Heroes and Demons" and Star Trek: Voyager, to be sure, and some that are far worse than the mis-depiction of the medieval in a single episode of a series that has an interesting premise and the ultimately unrealized possibility of excellent storytelling. The particular issue of the inept handling of the medieval, though, serves as a useful indicator of what else is wrong with it, one of many flaws that has led to prevailing disdain for the show. That disdain does much to argue against the value of a franchise that has offered much to many across decades, which is saddening to see, even if, in such a case, deserved.