I put the item on the rock stone and went underground. what the hell do I do next??
It's hard I think... have you talk to 32 people in underground? Once you have obtained the Odd Keystone, put it in the stone and you must go underground and TALK TO 32 PEOPLE! annoying, huh?
Here... you must steal 100 flags, talk to 32 people, and put the odd key stone in the lost tower. The keystone will be given to you by a woman on the left of Hearthome, and the tower is on the trail to the right.