As a Pokemon Trainer now traveling through the Sinnoh region, you stop to take a break... Only to see there was a double of your partner Pokemon... then a third. Before you could do something, you hear a voice call out.

Hey, you! Over here!

You look to see a girl come out from the brush before looking at the three Pokemon in between your two.

Alright, you two, get back over here!

Two of them suddenly glow and morph into Ditto... That explains it. Anyway, the 2 Ditto approach the girl as she addresses you.

See, here's the deal. Ditto 1 and 2 here are my pride and joy... but they love a good prank, so they always run off and pull stuff. My name's Narissa! Back where I come from, they call me "The Rumbler"! Wanna fight? I'm ready.