the story: Various members of the crew are confronted with representatives of an alien species studying them in unexpected ways.
what it all means: This was a lighthearted and easy way to follow-up the heavier "Descent, Part 2," exploring well-established character traits among the crew, whether Troi's easy-going nature, Worf's perpetual unease, or Picard's skepticism at even the most straightforward scenarios. Obviously the meat of "Liaisons" is spent on Picard's story, which is itself a follow-up to the numerous episodes he was featured in during the sixth season, but the full weight of the story is spread around, in ways that weren't always successful in the series.
Still, it's clearly not an ambitious affair, and it relies entirely on a reveal at the end of the episode, and that in itself is a tricky thing to pull off. In a way, "Liaisons" is a throwback to prior episodes in the series that explored day-to-day life for the crew ("Data's Day," which similarly tacked on an unneeded dramatic twist, for example), while also giving Picard a fairly generic predicament and mystery to resolve, who that person is who he's found similarly shipwrecked, even though all the pieces of her story don't quite seem to add up.
- franchise - It reflects similar first-contact turnabouts from the franchise.
- series - It generally reflects well on the series itself.
character- It doesn't add anything to the understanding of any particular character. essential- It is not essential in any regard.