In a nutshell, you assume the role of a human turned into a Pokémon character (originally based on the results of a personality quiz), and inadvertently partner up with a real Pokémon who finds you in the wilds (your character has no idea who you really are, you just remember your name and that you were human). You form either a team and recruit other Pokémon, who try to help you accomplish various missions. It sounds a little repetitive, but it's actually pretty addiction. BTW, it's also a dungeon crawler, if that's any reference.