Gustav Renker

Junta is hated by the people in the village where she lives, especially by the women, who suspect her of being a witch. Only she can climb the nearby mountains to a cave high up, whence a mysterious blue light glows when the moon is full. Many young men of the village have died trying to follow her. She is driven out of town, and takes to living in the mountains. Eventually she shares the secret of the blue light with one man, and he betrays it. (imdb)

When a young man returns to his estate in an Alpine valley, he finds a civil engineer, engaged to his childhood sweetheart, is threatening the mystical peace of the forest by trying to unloose a water source there. (imdb)