Conan's rich friend, Sonoko, is in auction hall with her famous grandfather in a skyscraper in New York. The highlight of this auction is one of Vincent Van Gogh's Master-piece in his “Sunflowers” series. It claims to be newly discovered addition to the seven Arles series of Sunflowers. However, the painting looks exactly like an authenticated one found previously in Japan called “The Second Sunflowers”. Nobody knows which one is real.