President Ito, a major apparel maker, was poisoned in the president's office. Kenzo (Baku Ohwada), who happened to be interviewing nearby, rushes to the site. According to his secretary Masae, Ito's ex-wife's younger brother Yoshimoto visited and he started arguing with Ito, but he suddenly escaped. Kenzo asks Kyosuke Kozu (Masaomi Kondo) to investigate. It turns out that Ito's son Takashi, who was killed, is enrolled in Kyosuke Kamizu's university. When Kyosuke Kamizu met at the university, his mother-in-law, Yoko, aimed at his father's fortune and said, "I think he teamed up with designer Kawahara ." Yoko has a relationship with Kawahara, and Ito, who died, was confused because she had an affair with her secretary, Masae. Takashi is said to have already left home and is living on his own.

The 7th popular suspense series based on the original work by Akimitsu Takagi. Along with Kogoro Akechi of Ranpo Edogawa and Kosuke Kindaichi of Seishi Yokomizo, Masaomi Kondo will play Kyosuke Kamizu, one of "Japan's Three Greatest Detectives", and will solve numerous challenges! A threatening letter foretelling the murder of the entire family came to the house of Tobe, who presides over the infamous investment group. Kumiko Toki, the third daughter of the family, consulted with the police, but she simply thought it is done by someone who recently lost investments. Kenzo, a reportage writer who was listening, became interested and brought the threatening letter to Kozu, asking him to investigate...

The sixth popular suspense series based on the original work by Akimitsu Takagi. Kyosuke Kozu was invited by former actress Shinobu Yuki, who had previously appeared on a magazine, to announce the production of the drama. The producer is Kako's husband, Fujita. When the press conference was about to end, the leading actress Hitomi was shot dead. She is suspected of being abandoned by Hitomi, her nephew Mizukami, but there is no evidence. Subsequent investigation reveals that Hitomi has been dating Urushida for three months. A few days later, Kako showed Kyosuke three threatening letters stating "Your life will be end in 10 days"...

Newspaper reporter Kenzo let a strange woman Emi took taxi while on the way home from a business trip. Later, when he stopped by his girlfriend Nobuko's house to give her souvenir, he noticed that the suitcase had been replaced by Emi's. A knife with blood wiped out came out of Emi's trunk. Nobuko's older brother Kyosuke is a university professor, but he is also a famous detective. The next day, Kyosuke made Kenzo follow Emi's elder sister, Yuri, who came to exchange the trunk. Emi and Yuri are daughters of the landowner Kayama family, but they were both children of their ex-wife. His second wife, Shizue, has Miyako, another kid. Emi had a bad time with Shizue and left home, and she had just returned for the first time in three years...

Kenji, a disciple of the famous detective Kyosuke Kozu, had a strange experience in the world. He was asked by a woman named Shoko Ima to find the corpse in the soil. Shoko is a famous dancer in the modern ballet world, and she just married doctor Fujimoto 10 days ago. However, on that day, Shoko had disappeared. Her corpse seems to be at the base of the ginkgo tree in the house of the sculptor Kagawa, who was rumored to have a romantic relationship. Police arrested Konosuke. However, Kagawa was also suspicious.

名探偵・神津恭介の活躍を描いたシリーズ第２弾。二億円のダイヤをめぐる密室殺人事件の巧妙なトリックに神津恭介が挑む。政財界の黒幕で、サラ金社長の森島（滝田祐介）が宝石の商談中に殺され、二億円のダイヤが盗まれてしまう。その場に同席していて、事件直後に姿を消していたマキと名乗る女（MIE）が怪しまれたが、現場は完全な密室状態。インタビューのため、現場に居合わせたルポライターの研三（大和田獏）は、大学教授で推理の天才・神津恭介（近藤正臣）に相談をしようとしたとき、マキとそっくりなモデルがテレビに映った…。

複雑な家族構成の資産家を舞台に、次々と起こる血なまぐさい惨劇。名探偵神津恭介シリーズ第５弾。「新聞記者の研三は出張の帰り、見知らぬ女恵美をタクシーに同乗させた。土産物を渡そうと恋人の信子の家に寄ると、スーツケースが恵美のものと取り替えられていることに気がついた。

犯人が仕掛けた連続殺人事件の巧妙なトリックを、神津恭介が得意の推理を働かせて見破っていく。刺青コンクールを取材していた松下研三（大和田獏）は、コンクールの優勝者で大蛇の刺青を持つ女・絹枝（高田美和）と一夜を共にした。だが数日後、その絹枝が自宅マンションの浴室でバラバラ死体となって発見される。完全密室での犯行だったため、捜査は難航。そこで研三は、恋人・信子（叶和貴子）の兄・恭介（近藤正臣）に相談を持ちかけたところ、密室の謎は難なく解けたものの、犯人をまだ特定できずにいた。

犯罪心理学者で名探偵の神津恭介(近藤正臣)は、妹の信子(森口瑤子)がツアーに参加する縁で旅行会社の記念パーティーに招待された。ところがパーティーの途中、旅行会社社長の妹・綾子(阿曽靖子)が何者かに射殺される。その犯人の手掛かりも掴めないまま、予定通りにパラオ島へ出発した信子がダイビング中に行方不明になったとの連絡が届き、恭介は信子の恋人・研三(大和田獏)とともにパラオへと向かう・・・。

インチキ投資グループの会長・卜部(根上淳)宅に、一家皆殺しを予告する脅迫状が舞い込んだ。卜部の三女・土岐子(大場久美子)は警察に相談するも、ろくに取り合ってくれない。そばで聞いていたルポライターの研三(大和田獏)は興味を抱き、神津恭介(近藤正臣)に調査を依頼。ところが翌日の夜、長女の澄子(八神康子)は刺殺体で発見され、さらに数日後、今度は次女の烈子(増田葉子)が炎に包まれて殺害されてしまう・・・。