At the moment I'm playing as Dawn in Pokémon Pearl, so I've been trying to go to Lucas' sister to ask where the swarm is, but all I get is questions like; who are you? and statements like; You're doing that Pokedex thingy for the professor! and; Wow! That's the same as my big brother! Go for it!
So how do I find out where the swarm is and who do I ask?