Is love a disease? If so, why hasn't Harry Kim been vaccinated?
This is one of the Voyager episodes that does too much and at the same time, not enough. This would have worked better as two well-developed episodes rather than one partially developed one having two plots.
There's a great establishing shot where we zoom in on what looks to be a large space station. We continue zooming in through a window where we see Harry Kim about to be intimate with a female we've never seen before.
There's no back story setup here. We're just dropped right into the middle of things. It turns out this is not space station at all but an intergenerational space ship inhabited by a people known as the Varo. Voyager is already on the scene helping them make repairs. We don't know how Voyager met up with the Varo or why they agreed to help them. Janeway blathers something about wanting to understand intergenerational space ships since Voyager might become one. Let's hope not. The Varo are extreme Xenophobes. They explore space but only from a distance because they don't want to meet or encounter anyone. That alone would have made a great back story of how Voyager met up with them in the first place. It would have been worth at least a quarter of an hour. Naturally, there is a rebellion a foot among some of the Varo who want to break away from their forced isolation and interact with others. No doubt, they want to "seek out new life and new civilizations…To boldly go where no Varo has gone before…" In short, this is very good story just dealing with people like the Varo and their internal conflicts about being isolated. However, a lot of the story development and conflict gets set aside in order to support the other plot line.
Getting back to Harry and his Varo girlfriend, we find the second and no doubt key plot of the story. At first, Harry is brooding that he's breached Starfleet protocols by being intimate with Tal. However, he soon starts glowing indicating his girlfriend has given him an STD (sexually transmitted disease) and he needs medical attention. This exposes his affair to the Doctor and Janeway.
We learn that Starfleet has a lot of protocols about this sort of thing. Not surprising since STD's and even birth control involving humans and aliens would probably be of major concern. Janeway orders Kim to stay away from the woman.
Harry finds he can't stay away from her. He "borrows" a shuttlecraft and takes her on a ride. Naturally, he gets caught. The Doctor is convinced that Harry is acting out because of the alien virus which is establishing some sort of chemical interdependency between the two lovers. A comparison to human "love" is inevitable and Seven of Nine speculates that human love too is a disease. Kim insists the virus is not the cause of his disobedient behavior but that he has to go with his feelings. Janeway wants to believe Harry is misbehaving because of the virus since Harry has always been a great Starfleet "lapdog." Where has Janeway been the past several years? This is the way Harry Kim always behaves. It's more like he should be called "Horny" Kim rather than Harry Kim. In fact, in this episode, Tom Paris states outright that Harry is always going after "unattainable females" and sites some past Voyager episodes to prove it. Considering this is out of a character's mouth, it's probably makes sense.
Like the other episode plot, this one ultimately doesn't do enough. We don't know enough about Tal and what she sees in him or him in her. This is a common problem in Voyager "one-episode-romance" stories. Also, Tal is part of the Varo group that wants to go out and explore space but she's not interested in joining Harry on Voyager or asking him to join her. It all seems very contrived.
Harry's ultimate decision not to have medical help to get over his "condition" also seems contrived. Why not? What is he proving? That he's better than his own chemistry or chemistry induced by some virus? It's difficult to marshal any sympathy or empathy for him which might happen if more time had been devoted to really building chemistry between the two lovers.