Okay, basics of Mystery dungeon. Here's hoping I don't forget something important. :o
In the mystery dungeon games the whole thing is run by pokemon. Pokemon are just as intelligent as humans, but they don't have much in the way of technology. They have villages and stores and form guilds, but there's no electricity. They don't make armor or weapons since that's usually covered by the fact that pokemon can fight fine without those things.
In Mystery Dungeon there are some pokemon that choose to form 'Rescue Teams'. The purpose of these teams is to go out and help other pokemon. Usually there will be a like a new board somewhere in town listing all the jobs available for a rescue team. Your team will accept a job and go to the mystery dungeon where the job is located. Mystery dungeons are mysterious because every time you go into them, their layout changes so each time it's sort of a different experience.
From what I've seen your team will always have competition from other teams, but in some cases a group of teams will form a guild. Guilds usually share housing and food, and whenever there's a job too big for one team, the guild will work together to take care of it.
In both of the two games I've played you're a human who was turned into a pokemon and you join a rescue team while you try to recover your missing memory. Then the world will be in danger and you save it, but we don't have to do that unless you want to.
Or, if all of that seems like a bit much to figure out all at one time, I'm down for a regular pokemon rp too, as long as it's from a pokemon point of view. Also, I fully recommend the games. They're loads of fun! :3