Seiya and his friends receive an extraordinary request from the owner. The request is to steal a ring said to have been made by da Vinci from the mansion of Ichiro Tamada, the leader of the Tamada crime syndicate. For preliminary investigation, Seiya disguises himself as an electrician and enters the mansion, where he becomes intrigued by the lively party being held there. The party is a private celebration for the marriage of Ichiro's son Isao to the daughter of the Kawaguchi clan leader. In the center of the hall where the party was held, along with sake and finger foods, was the ring in a glass case. The party goes smoothly, although Ichiro's father and chairman Shigeo, who is opposed to this marriage, arrives at some point during the party. Ryosuke, in the midst of all this, confirms the laser sensors that are all over the mansion. Seiya and Ryosuke return to the office and decide to do a rehearsal using the strings.

• Daisuke Terasawa
• Kazuhiko Ban

• Shirō Sano
• Mikako Ichikawa
• Noriyuki Higashiyama