As the series begins, thirty-year-old Astrid Nielsen is an autistic woman who works discreetly as an archivist for the judicial police, and knows every case she has handled.She meets Raphaëlle Coste, then in charge of an investigation into the suicides of doctors. The two solitary women help each other, Astrid offering Raphaëlle a methodology; Raphaëlle offering Astrid behavioral help in return.