the story: Stranded on an alien world, Tuvok faces a complicated relationship with a women he meets.
what it's all about: "Gravity" is an episode that feels different, possibly because it caters to an actor (Lori Petty) more familiar with working in movies (she was the star of Tank Girl) than TV (though she's done plenty of that, too). Some of its impact is dulled by next season's "Blink of an Eye," which also uses a planet that experiences time at an increased rate but to a more pronounced and deliberate effect.
So it really becomes a Tuvok episode. With all due respect to everyone who argues Chakotay barely has much a role in the series, at least he got far more spotlight episodes. Being a Vulcan in a franchise known for a particular Vulcan (Spock) and not being that Vulcan, Tuvok was always facing an uphill battle. "Gravity" is kind of a Spock episode, but it spends its time explaining why Tuvok can't have a romance, and not so much because he's Vulcan or has a wife back home, but because of the particular circumstances in which he first embraced suppressing his emotions. It ends with him sharing via mind meld his thought process with the would-be lover. It's very much an episode that happens the way it does because there was a famous Vulcan before Tuvok, and so there were things that could be explored differently, and that's exactly what happens.
franchise- You may watch this and wonder if it breaks any new ground... series- Or wonder if it becomes negated by the later and more fanciful "Blink of an Eye"...
- character - But in fact, it's a lovely Tuvok spotlight...
- essential - That in its way helps further distinguish him from his more famous Vulcan forebear.