It would be interesting to see a Star Trek episode, or a stand alone movie that's not Trek at all that finds a sentient underwater species on a moon like Enceladus. Imagine never having a sky and not knowing about galaxies, solar systems, planets or moons or even space, it's all a new concept. Then having something melt it's way past the "upper barrier" (the ice), and bringing all that knowledge with them to your small little enclave near the hot spot where all 'known life' has always existed.
What would be more depressing, never having known about "the outside" or having that knowledge knowing you'll never be able to be part of it.
This is the kind of story that science fiction has been telling for decades. In books. Not everything translates well to movies or TV.