Nono is brought up by her father and his partner Gaby. The boy did not know my mother. His dad is a detective and has always been training Nono in this profession. Two days before his 13th birthday, Nono gets a special mission. He has to recognize his teacher on the train and go to training with him to become a real detective. A series of adventures begins, because as a mission Nono chooses two things: get Gaby artifacts that she has always dreamed about and learn about her mother. A solution to the riddles awaits him, and his mother's story turns out to be more confused than anyone could have imagined.