Speak with
Ylang
Enter house near
Ylang
Find place with
Tempdragons. Kill them and put
White Dragon's ball on buttons to open bridges
When You find place which says You are not heavy enough, collect 5x
White Dragon's ball and step on button
Now take
Black Dragon's ball
Come back to the beginning and step on this button
Find and speak with
Mi or Tan to finish the quest.