By the time "Russian Flu" rolls around, were deep into the excellent first season of Northern Exposure, the few 'opening night jitters' that plagued the show for the first half of the season are gone, and the cast and crew are turning out some really fantastic television on a regular basis.
Additionally, we're treated to the introduction of that tried and true sit-com convention - the visiting relative (or, in this case, fiancee) trope. A trope the writers would come to rely on frequently, not just for the rest of season one, but for the duration of the show.
And, while this convention is so often annoyingly associated with the latter seasons of well-worn sit-coms, vainly attempting to inject some measure of life into a show that overstayed its welcome years prior, in the case of the first season of NE, the result is often spectacular.
Rather than focusing on the main cast of actors early on in the show's run, we get to meet their fiancees (Russion Flu), brothers (Aurora Borealis, a Fairy Tale for Big People) and ex-husbands, among others. This has the effect of taking the spotlight off of the main characters, thus increasing their 'shelf-life' in the eyes of the viewer; if it takes us longer to get to know these characters, then, theoretically, it may also take us longer to get tired of them. Similarly, by focusing on relations, rather than main characters, the show's writers don't have to worry about running out of ideas for their main cast as quickly either. As interestingly quirky as the denizens of Cicely are, that quirkiness is a finite resource, best not to blow your wad right out of the gate.
As always, the formula that makes this episode enjoyable for me is no different than the formula I've referred to else-where in these NE reviews: eccentric characters, involved in eccentric situations, all underpinned by a generous helping of adroitly applied light-comedy, good television ensues.