I’m looking for a solution roughly equivalent to “cast sending.” However, the NPC is not a wizard, and there is no wizard nearby who knows the player-character. The NPC does not know where the player is, so Animal Messenger will not work.
Message length needs to be at least a few words, although longer is fine. Ideally it should be affordable for low level characters without much wealth. Distance between parties is about 80 miles and on the same plane.
I’m looking specifically for a Rules-As-Written answer. I know that as GM, I can just make up anything I feel like; pointing that out is not helpful.