Crap. I talked to the shopkeeper in the lower left-hand corner, but I forgot what he said, do you know who's after him?
(hey by the way Ame this is a serious complaint - if an NPC wants you to go a certain direction, he should keep telling you that until you've gone to the next guy, otherwise it's way easy to get lost)
EDIT: I found him. He didn't appear until I entered the pokemon center equivalent just outside the watering hole one guy directs you to and then left. What the hell.