The Secret of the Vanished Masterpiece The Detective Boys decide to investigate a spooky château but realize a man is currently inhabiting the house and had remodeled the garden. The next day, the man living in the château, Rokuro Wada is revealed to have died. They learn from Keiichi Yagami, Wada's agent who sells his paintings, that Wada had been working on a masterpiece at the château for three months. They decide to search the château for the painting but to no avail. Afterwards they are visited by Wada's old aunt Saeko Takatoo and her caretaker Mina Eguichi who reveals that Wada sent them a letter telling them to visit the château tomorrow to view the masterpiece...