John Clifton follows the pilgrims' way across the Massif Central. He is on a journey of self discovery, when the gendarmes recruit him to help with a series of murders near the village of Petite Bastide d'Olt. A bizarre painting of a White Mare in his bedroom disturbs him, and he dreams of making love to his hostess. John's erotic dreams turn into nightmares, as supernatural powers compel him to ride the White Mare. Horse and rider fly over the village and the countryside in the dead of the night. He cannot believe his dreams, and looks for a rational explanation. But there isn't one. The past constantly intrudes into the present. A malicious phantom world overlaps the real one. John's very survival is drawn into question. Will he find an answer?