It's generally set around a Tournament (Thus the name 'The Argent Tournament')
Basically, when a person enters the Tournament, they are joined with a group of others (The other RPG'rs), and the group battles against others in an attempt to win.
Is there a limit to how many they can know? Like.. for the games you can only have 4 for pokemon, and in the anime I think they have like 5 or so.. That's what I was asking more I guess, but that's good ^_^