help

Go to world 3-3, accept a quest from NPC Then go to world 3-2, and go to class D, finish the quest and the mirror opened

Did anyone know how to make the rock at Class room C explode ? I have try to ignite the fire with book but it break before reach the corner or else throwing won't ignite the bomb too. :(

Just throw the burning book in the direction of the book that is near the bomb, the book (near the bomb) will catch fire and also burn the bomb.