Conan investigates and realizes the warehouse is designed by Samizu Kichiemon (三水 吉右衛門) and that the abacus is the switch that will reveal the secret room. The Detective Boys and Conan have the owner of the warehouse call the police before revealing their deductions. When the police arrive, the Detective Boys explain that the warehouse has a low ceiling which was concealed by the interior design of the warehouse. A fake window was installed inside the warehouse to mimic the distance between the window and the ceiling outside the warehouse. Conan then explains if the abacus is arranged as to display the Kanji Samizu (三水), the ceiling would lower revealing the secret room. After doing so, they discover a man in the room. They learn that the man was a serial robber and the treasure was all stolen good. Conan then reveals to the Detective Boys that he discovered Heiji had been giving them advice during the investigation and forces Heiji to come out of hiding.