Wonder Boy in Monster World/Alsedo, the fairy village

Alsedo: The Fairy Village
Stand between the two pillars in the middle of the village and press up. You will be transported to queen Eleanora. Talk to her, she will entrust one of her helpers to you, Priscilla. Priscilla will give you a small heart each time you have defeated 5 enemies in the same area.

Go back to the village and collect some money. Buy the equipment (Wood Shield, Small Spear and Chain mail) from the shop called Kishera and Medicine from the shop called Felissimo. After this talk to Sonia. She will tell you that she lost her Ocarina somewhere in the cave. Go find it. If you return it, Sonia will teach you the songs to open the doors in the cave. To open them stand on a platform with the music notes and use the Ocarina. Now play one of these melodies.
 * Blue door: B A B A B C B
 * Red door: A B C B C A B
 * Green door: A C C A B A B

Inside the cave you will come across a chest. Open it and you will receive an extra heart. Continue along until you reach the boss door. When you pass the pillar a heart will fall out of it. This can be repeated about three times. Enter the door to fight the Myconid. After you've defeated it you receive some gold and three more units of Fire Storm. Leave the village through the hole in the tree to the far left of Queen Eleanora. Before you leave make sure you've got at least 400 gold. There are no more monsters in the town itself, but you can still return to the forest and the areas beyond it for mushroom hunting.