Cactus Game Design Message Boards

So I was looking this card over and wanted to know if it is a "do x to do y" kind of thing or "do as much as you can" thing.

Lingering in Sodom:  You may play a City from deck.  If played in battle, capture opponent's character of opposite alignment to an unoccupied Genesis Site.  Cannot be prevented.

So the question is on the "in battle" part.  Say neither player has a Genesis Site, or any they do is already occupied.  Does that mean you don't get to capture the character?  If it is a "do as much as you can," you still get to capture, but I'm not sure you can based on the wording.

I'm pretty sure there has to be both a character of opposite alignment and a site to target in order for the ability to even work. (I don't know where to reference the REG in this situation)

That's the answer I got when I asked the question. I'm not sure it's in the REG - and if it needs to go in, I don't know where it goes.