Synopsis

The culprit behind the Duke of Le Mond's death and the theft of his opal is revealed: it is Lupin. Detective Conan Dorill, piecing together the clues, anticipates Lupin’s reappearance at the costume ball, where he intends to murder Count Johannes’ daughter and seize a second opal. Yet, this act of vengeance does not satisfy the true Lupin. Professor Dolmen possesses the third opal. How will the ancient Incan treasure, steeped in hidden revenge, ultimately be resolved?