Excitement at the riding tournament. Who is behind the strange incidents at the show jumping competition? What exactly happened during the obstacle course? Together with their three friends Kim, Franzi, and Marie, children help with the investigations at the horse farm. The included short story immerses them in an exciting case. Piece by piece, the young investigators find important clues that lead them closer to the culprit. A brilliant extra: a mysterious secret box containing a crucial piece of evidence. Can the children combine all the clues correctly and solve the case?.