Gédéon, the Count of Niedeck's gamekeeper, visits Dr. François to invite him to the chateau. He explains that his master has suddenly gone mad during a change of moon. En route, the two men meet a strange old woman who lives in the woods. Gédéon explains to the doctor that whenever this woman prowls around, the Count is plagued by dementia. Once there, the doctor treats the Count and calms him down. The Count has a daughter, Odile, whom he clearly hates. One evening, a mysterious traveler arrives.