The Fire Spell is one of the eight spells that Link can learn in Zelda II: The Adventure of Link. It allows Link to shoot fireballs from his sword instead of beams, but does not require a full health bar. While not vital in order to complete the game, the Fire Spell is the only means by which Link can defeat certain armored enemies in the overworld.
Link obtains the Fire Spell in Nabooru Town, located in eastern Hyrule. By first going to the fountain to fetch water for a thirsty young woman, Link is allowed to see the wise Old Man living in the basement.