I'm starting a new game tomorrow and I'd like to throw something unusual at my players. The setting is a typical Tolkien-esque setting and the players are aware of that..but I'd like to introduce clockwork and steam as an unknown and mysterious thing they would discover.
I don't want to ask them: "Hey, you guys are cool if the campaign leads to a clockworks and steam-powered soldier invasion?". I want this to be a surprise and also I want to avoid metagaming.
The plan is to make them visit a very old dungeon in which there would be clockwork soldiers. I would make them pass as strange armors standing in rows.
I don't want to ask them if clockwork soldiers themed campaign is ok with them for the following reasons:
- They would be expecting the "armors" to be clockwork soldiers and prep for it.
- It wouldn't be strange or mysterious when they find about it
- They could prepare for it or get paranoid about every piece of metal in the dungeon.
The thing is..I know from experience that having a certain genre or setting imposed on me as a surprise often turned out to be bad. I don't like playing a game when suddenly the GM hints that we actually are in The Matrix...or that the game will be about an undead invasion and I didn't want to play "that kind of game". I don't know if clockwork and steampunk will pass as interesting plot twist or uninteresting attempt to spice up a setting.
So my question is: How can I introduce twists to the setting without asking them in advance if what I plan fits in their liking and taste.