In ST:VOY 2×22 "Innocence", Tuvok is trapped on a moon with a bunch of children from a nearby world. It turns out the apparent children are actually old people, as the respective species "ages backwards" (whatever this is supposed to mean – it sounds completely nonsensical to me).
In any case, Memory Alpha’s background information section seems to imply the original script by Anthony Williams had a different resolution to the story. It indicates this several times, but weasels around describing what was different about it:
- "Although the premise for this episode was pitched by Anthony Williams, it was slightly different from how the story turned out and Lisa Klink was not completely in favor of the initial idea." – but in the following, the text only revolves around the premise rather than the resolution.
- "Lisa Klink struggled to come up with a science fiction twist to the story." – this clearly states the twist ending about reverse aging was not in the original script. Thus, either there was a different twist ending (that is somehow not given away on MA, or in the source it cites), or there was none (in which case it is not clear why one had to be added, given that the episode focused on the social aspects of having a Vulcan care for children).
- This is followed by an even more explicit statement: "We didn’t end up going with [Anthony Williams’] sci-fi-premise, but the idea that something mysterious was happening to [the kids] kind of stayed with it, and it ended up being the reverse-aging thing." – thus, obviously there was a different sci-fi twist that explained the kids’ disappearance.
Is it known what the sci-fi twist in Anthony Williams’ original script was?