It is not exactly known what happened to Lucy. Lois and Lucy separated from their camp group one day while on an excursion. The other campers were nearby. Lucy had to use the bathroom, and Lois offered her friend some toilet paper. Lois climbed over some boulders until Lucy was out of sight. She wanted to give Lucy some privacy. Then Lois heard "a cry of surprise, cut off too soon" from Lucy ("Death by Landscape"). It was "short, like a dog's bark." Lois went back to the spot where she had left Lucy, but her friend was not there.
Lois and the other campers searched for Lucy. They used their canoes and looked all around. They could not find her. Then police went out with motorboats and search dogs. They, too, could not find Lucy. The girl had vanished. She was never found, and Lois forever lived with feelings of emptiness.