The Jet-Black Diamond

A dark auction held in the basement of London. The exhibit was the treasure of "Sieg the Pirate King" who was executed in a Brazilian prison after a rampage in the Atlantic Ocean 100 years ago. However, Lupin's aim was an old kokeshi doll that was lost in it. Police officers invade the venue. During the confusion, Lupin obtains the map hidden in the kokeshi doll. This map shows the whereabouts of the undiscovered Sieg's treasure, the "Jet-Black diamond".