The body of Jenny Peyrac was discovered, the wrist broken and the skull smashed by a jack, in a cement factory. What could have brought this young professor into such a trap? Lieutenant Diakouné may have a lead: she is wearing an electronic bracelet for a robbery committed several years ago. Alice followed Chahine's advice, only hypnosis can help her to trace her memories and discover who is this dead man who comes to haunt her...
