Nutshell: Par for course. Pretty superficial, particularly near the end, but a fairly diverting hour.
When Ensign Vorik finds himself at the mercy of his first Pon Farr cycle, the Vulcan mating instinct, he announces to Torres his desire to take her as his mate. She refuses, at which point he briefly attempts to force a mental bond between them—before Torres slugs some sense back into him. Because of the failed bond, Torres soon finds herself with the same chemical imbalance Vorik has, and must fight her own sexual urges. Intertwined with this situation is a subplot within the caves of a vacant M-class planet containing a valuable mineral which Torres, Paris, and Neelix beam down to retrieve.
"Blood Fever" is basically "Amok Time" in the Delta Quadrant, where a Vulcan does not have the luxury to return home to take a spouse. This is not an extremely deep episode of Voyager, but it is effective on its own terms. The best single-word recap for this episode may be "entertaining." Then again, words like "shallow" and "glib" also come to mind.
The early acts work fairly well, as Doc attempts to help Vorik proceed through the Pon Farr with medical assistance; to which Vorik answers that it's merely a "Vulcan" matter that he has to resolve on his own with meditation. "How well a Vulcan deals with the Pon Farr is a test of his character," Vorik tells the Doctor, refusing to discuss it further. A subsequent discussion with Tuvok gives Doc little further enlightenment.
Much of the early material (for those who are not already familiar with the Pon Farr from TOS's "Amok Time," that is) is background about Vulcan mating cycles (i.e., every seven years an adult male must either (1) take a mate, (2) fight a ritualistic battle of competition, or (3) resolve it with deep meditation—or else the chemical imbalance could kill him). None of this stands out as particularly special, though it is sensibly handled with some occasional bits of effective dialog. One interesting exchange in particular reveals some perspectives:
Doc: "For such an intellectually enlightened race, Vulcans have a remarkably Victorian attitude about sex."
Tuvok: "That is a very human judgment, Doctor."
Doc: "Then here's a Vulcan one: I fail to see the logic in perpetuating ignorance about a basic biological function."
Tuvok: "There is nothing logical about the Pon Farr. It is a time when instinct and emotion dominate over reason."
Doc comes up with an alternative for Vorik, by programming him a holographic "mate," which, as Doc puts it, may be able to help him with the short-term problem. The solution appears to work at first (though I don't quite understand how Vorik would form a telepathic link with a computer program).
As Vorik's situation is analyzed on board the Voyager, Torres begins slowly losing control as the chemical imbalance begins to release her Klingon urges, interfering with the away mission in the caves. Worse comes to worse when it's revealed that the planet isn't truly vacant, but occupied by a race of aliens who are hiding underground. The aliens transport out of the area, taking Chakotay and Tuvok prisoner, leaving Torres and Paris alone, lost in the caves.
The aliens are suspicious of outsiders, ever since they were attacked and conquered more than a half century ago by a powerful group of unknowns, in a swift defeat that left them ruined in less than an hour. Chakotay negotiates a trade with Ishan, their alien captor (Bruce Bohne) after assuring them Voyager isn't a threat.
The remainder of the episode is mostly devoted to the issue of B'Elanna's intense need to appease her case of "blood fever" by using Tom's, well, male presence; which, as one could probably expect, is where the character core of the story lies. Dawson, as usual, delivers a compelling performance, creating a instinct-driven B'Elanna whose mental awareness strives to remain in control over the vehement, irrepressible desires. Tom plays the part of a good guy—making sure B'Elanna doesn't do anything she'll later regret—and him too, given that B'Elanna is someone he's been subtly chasing after for months.
On more than one occasion she throws herself at him (literally), but Tom handles the delicate situation as best possible—pushing her away because it's in the best interests of their friendship. Both Dawson and McNeill are believable in the extreme situation—the former as a distressed, confused person pushed to the limits of sanity and her own endurance and ready to crawl out of her skin; the latter as the calm, cool-headed sense of reason and survival. Amidst the background of some handsomely-produced cave-ins and rock slides, the results are good.
Unfortunately, the conclusion, like many episode conclusions, does not have a payoff that's in sync with the rest of the story. As Torres and Paris are rescued by Chakotay and Tuvok, Torres' time runs out, and the away team loses contact with the ship. Tuvok explains that Paris must "help" Torres now, or she will die as a result of her chemical imbalance. I didn't necessarily have a problem with this—in fact, to see what would've happened as a result of this extreme solution to such an extreme situation could've potentially been interesting (although I don't see how it could've been pulled off without seriously risking the apparent friendship between these two characters).
What does strike me as superficial, however, is Vorik's appearance out of nowhere (apparently Doc's holodeck solution was a failure) to assault Paris and claim Torres as his mate. This leads B'Elanna to face Vorik (in accordance with Vulcan tradition) in a glib fight scene concept that's straight out of "Amok Time"—an idea suited more to the lighter hokiness of TOS's reign. This fight, like much of the show, is entertaining and kind of fun; but as drama goes, it's as transparent as a piece of Plexiglas. The stuntwork is decent, but Chattaway's "action" score could use work. Alexander Enberg's portrayal of Vorik in the closing struggle is annoyingly overacted; Dawson, on the other hand, remains within the realm of credibility.
The fight purges the "blood fever," as upon B'Elanna's, er, KO of Ensign Vorik, Tuvok announces that both will return to normal.
What does "Blood Fever" add up to besides a diverting hour? Not tons, but there is a hint that Torres will look at Paris differently from now on because of what he did for her.
What will be most impacting from this episode, though, comes with Chakotay's discovery of a dead invader in the ruins of Ishan's world—a Borg. (That's right, Voyager crew, there are Borg in the Delta Quadrant to keep you company.) This revelation works because it certainly makes sense that the Borg would be behind an attack like this—and a Borg threat could also potentially re-energize the series. (I'm looking forward to next week's "Unity" in particular.) Still, this revelation would've been much more powerful had it not been shown on last week's trailer. So it goes.
I think that a very low-end "good" seems fair for a rating of "Blood Fever." Glib entertainment is still entertainment.