(...) The young Detectives are very happy that the Easter holidays have arrived, giving them the opportunity to relax from their studies. An entomology conference, organized in Peterswood, brings a crowd of people to their area, many scientists, but also an escapee from prison, with a horrible scar on his face - the marked one - who becomes the fear and terror of the region. The children soon get involved in the search for him, without suspecting what awaits them. [Excerpt from the text on the back cover of the edition]