. 1960-1970's A young woman with long, straight blond hair, in her late teens or early 20's is the lead character, possibly accompanied by her little sister. There is some sort of supernatural mystery involving the disappear of another girl years before. She seems to have disappeared when a group of children accidentally perform a magic spell. In one scene the blond woman sees a glowing symbol in the fog over some water, leans in to get a better look and falls into the water. At the end of the movie, the blond woman and the other people originally involved with the spell gather together to reenact the spell and bring the lost girl back. They are in an old stone building (church, tower?) and the spell ends with a huge bell falling from where it hung above them and the lost girl being brought back.
I saw this in the early 90's, possibly on the Disney channel or another family friendly channel. Never saw the whole movie, and it's bugged me ever since.