The following is an excerpt from Myths & Legends of Japan by F. Hadland Davis, available from Project Gutenberg.

Yosoji's mother, in common with many in the village where she lived, was stricken down with smallpox. Yosoji consulted the magician Kamo Yamakiko in the matter, for his mother grew so ill that every hour he expected her to be taken from him in death. Kamo Yamakiko told Yosoji to go to a small stream that flowed from the south-west side of Mount Fuji. "Near the source of this stream," said the magician, "is a shrine to the God of Long Breath. Go fetch this water, and give it to your mother, for this alone will cure her."

Yosoji, full of hope, eagerly set forth upon his journey, and when he had arrived at a spot where three paths crossed each other he was in difficulty as to the right one to take. Just as he was debating the matter a lovely girl, clad in white, stepped out from the forest, and bade him follow her to the place where the precious stream flowed near the shrine of the God of Long Breath.

When they reached the stream Yosoji was told to drink himself, as well as to fill the gourd with the sparkling water for his mother. When he had done these things the beautiful girl accompanied him to the place where he had originally seen her, and said: "Meet me again at this place in three days' time, for you will require a further supply of this water."

After five visits to this sacred shrine Yosoji rejoiced to find that his mother was quite well again, and not only his mother, but many of the villagers who had also been privileged to drink the water. Yosoji's bravery was loudly extolled, and presents were sent to the magician for his timely advice; but Yosoji, who was an honest lad, knew in his heart that all praise was really due to the beautiful girl who had been his guide. He desired to thank her more fully than he had hitherto done, and for this purpose he once more set out for the stream.

When Yosoji reached the shrine of the God of Long Breath he found that the stream had dried up. With much surprise and not a little sorrow he knelt down and prayed that she who had been so good to his mother would appear before him in order that he might thank her as she so richly deserved. When Yosoji arose he saw the maiden standing before him.

Yosoji expressed his gratitude in warm and elegant language, and begged to be told the name of her who had been his guide and restored his mother to health and strength again. But the maiden, smiling sweetly upon him, would not tell her name. Still smiling, she swung a branch of camellia in the air, so that it seemed that the fair blossom beckoned to some invisible spirit far away. In answer to the floral summons a cloud came down from Mount Fuji; it enveloped the lovely maiden, and carried her to the sacred mountain from which she had come. Yosoji knew now that his guide was none other than the Goddess of Fuji. He knelt with rapture upon his face as he watched the departing figure. As he gazed upon her he knew in his heart that with his thanks love had mingled too. While he yet knelt the Goddess of Fuji threw down the branch of camellia, a remembrance, perhaps a token, of her love for him.