A fifty-year-old police officer, Michèle Varin, finds herself in a highly depressive state due to the death of her young son a few years ago. In one way or another she feels guilty for his death and feels particularly bad every four years during the period of time around 29th February, the anniversary date of the boy's demise. Such is her unenviable condition when she is assigned a trying ordeal (at least for her):investigating the case of a woman found hanging from a tree in a forest. Horror follows her trail, but to what extent is this reality or one of those nightmares she has and her shrink has been unable to rid her of?