In the early 1950s the Alpine village of Marmorera and the surrounding valley was flooded because of a local dam project. Even today the sunken village hasn't been lain to rest. Then an unknown, confused young woman is rescued from Lake Marmorera, and soon becomes a puzzling figure of much concern for Zurich's psychiatrists. One of them, Simon Cavegn, himself originally from Marmorera, treats the young woman and slowly starts to discover the dark secret of Marmorera.