In the corner of the room is the mayor, curled in a ball position. 'Ah, thank the heavens, the hero. As you can see, we've been attacked, and the damage is catastrophic. There was a giant beast that spoke, and called itself corruption. Then it wiped out everyone. I'm the only survivor! Go in the shop and buy some equipment, then take the key in that chest and go into bluevilles storage chamber. In the storage chamber is the key that opens the path to Greenville. Check if there are any survivors there! You'll have to find the entrance to the storage chamber first though...

(Only use the key in the chest for the storage chamber, then use the key in the storage chamber to go to Greenville)