I wouldn't say never, but it seems like the kind of story that would kill the buzz. I like playing silly campaigns and it's hard to be silly about such things. I have run stories where the party finds captive people and busts them out, but it usually isn't a core component of the campaign plot. I have a storyline in the backlog that I've never used about sentient stones. Basically, magical crystals in the rock form neural networks. Some of them can think, some of them can communicate, but they are immobile and defenseless. they are routinely harvested for their magic crystals, and sometimes trafficked great distances. One of the campaign hooks centers around a stone that was used to prop up a table right next to a mill, close enough that it could hear the rocks scream as they slowly grind down to dust, every day, for years. It gets grim. I might run that one with the right table.