In a quiet town overlooking the sea a mysterious killer kills leaving as a rosary sign. This is intertwined in the hands of his victims in prayer. The case is entrusted to Inspector Roberto Parisi (Gabriel Garko), a serial killer specialist, a man from the dark past. When Parisi understands that all the victims of the serial killer are attributable to Santa Teresa - a returnee center for young people who are led by Sister Serafina (Angela Molina) - makes Angela go as a guest of that community. Thus Inspector Parisi, with the help of an ex-policeman, will find out who lies behind the impenetrable mask of the killer and with his investigation will emerge the inconceivable secrets hidden behind the perbenist façade of a normal Italian province.