Continuing from the last episode, Shinichi and Ran found the monitor panel with the date 27 May 2010. The case starts in a ramen shop where Shinichi and Ran were watching a fight between Noguchi Miki and Yuri at their father's funeral since Sonoko attended it since her dad was a close friend with him. Suddenly, Ran receives a call that Sonoko's been kidnapped. As soon as they arrived at the Hyogoro Ramen Headquarters, they were briefed by Miki that she got an anonymous call that her sister has been kidnapped along with Sonoko and demand 10 billion diamonds for their lives. Once they fulfilled the demands and oddly the diamonds disappeared without the kidnapper appearing, they receive a letter inside the box that they've received it and will release the hostages at Beika's Central Park and later directed them to the Headquarters underground depot. As soon as they rescued the hostages, they realize that Miki was strangled to death when they left her. After further investigation, Shinichi figures out that Miki was the true kidnapper to have the diamonds for herself however, Yuri murdered her sister since she was in cahoots with her plan. The proof is that one of the assistants picks up a bead that happens to be from Miki's necklace during the rescue in the underground depot. Yuri confesses however she told him that Miki was the one who plans it and probably left a dying message before she dies. Shinichi notices a strange sound at the air vent and opens it, as countless diamonds falls off from it.
Shinichi keys in 'Diamond' and the balloon deflates a bit and explode. As the both enter the next room, they feel a bit of electric shock and they both realize if they don't solve the next panel, both of them will be electrocuted.
ラーメン王・野口兵五郎の葬儀で野口の娘・由利と美紀が遺産を巡り骨肉の争いを展開した後、葬儀に参列していた園子が由利と一緒に誘拐されてしまった。犯人は身代金として10億円分のダイヤを要求し、野口の本社ビルのアドバルーンで上空に上げさせる。しかしダイヤは既に盗まれており、新一達は犯人の指示で園子達の監禁場所に行きつき2人は保護されるが、そのとき美紀は犯人によって殺害されていた。新一と蘭は、これまでよりも狭いホワイトルームに閉じ込められ、新一が壁面にあった画面にキーワードを入力後、膨らみ続けていたバルーンは萎んで割れた。入力したキーワードは「ダイヤモンド」。
