Rookie detective Tatsuya Sumire dreamed of being like the hot-blooded detectives who appear in detective dramas. However, the first order he gets from his superior is to infiltrate a programme as an idol in order to solve cases occurring in the entertainment industry. And so, the idol ‘Deka Dance’ is formed impromptu. Tatsuya is initially bewildered by the special world of the entertainment industry but somehow gets popular each time he solves a case. And then he gradually becomes aware of himself as an idol.
Kinshiro Toyama (Hiroshi Tamaki) is the new chief at Kitamachi police station. He is enthusiastic to solve cases which interests him. He bickers over pretty much everything with veteran detective Yozo Minami (Masahiro Takashima). Minori Aikawa (Miori Takimoto) is a rookie detective who wants to become a veteran detective.
Nagisa Kinomiya (Maki Horikita) is a detective for the 7 Investigation Division. The team consists of female detectives and they seek out female criminals and to help female victims. Nagisa Kinomiya has a special ability to hear the mind's of others. To shutout other people's emotions, she wears a headset, but, when working on a case, she uses her special ability. At crime scenes, Nagisa Kinomiya can hear the left behind voices of criminals and victims.
Catherine Turner is the daughter of the Vice President of the United States, and she had come with her father on his official visit to Japan. Since she runs a flower arrangement business back in the US, Catherine decides to stay on in Japan to learn Ikebana, after her father had returned home at the end of the official visit. Japan's Minister of Foreign Affairs, Hamaguchi Yukio, asks his nephew, Ichiro, to escort Catherine during her extended stay in Japan with the strict instructions that he is not to fall in love with her.
Catherine actually started her flower arrangement business after a chance meeting with a Japanese woman, Ogawa Maiko, who had held an exhibition in the United States. She befriended Maiko, and is now hoping to reunite with her old friend in Japan. Unable to reach Maiko, Catherine is shocked to learn that Maiko is a victim of a homicide. Thus, with the help of Ichiro, Catherine begins to look into her friend's death. -TV Asahi
Kyoko Okitegami (Yui Aragaki) is a private detective. She is known as the Forgetful Private Detective. When she wakes up in the morning, her memory is reset. Due to this, she rigidly adheres to a maintenance secret. No matter what case she has, she has to solve the case in a day. On her body, she has an important note that she must never forget.
Even though Yakusuke Kakushidate (Masaki Okada) has a crush on Kyoko Okitegami, he is alway mistaken as the culprit of a case by Kyoko Okitegami. No matter how close Yakusuke Kakushidate gets to Kyoko Okitegami, she totally forgets about him by the next day.
Hinako Todo (Haru) is a rookie detective assigned to the #1 investigation team at the Tokyo Metropolitan Police Department. She became a detective, because she wants to find the boundary between people who kill and those that do not.
She always carries with her a shichimi (pepper powder) bottle which was left by her late mother. She sprinkles the shichimi onto everything she eats. One day, Hinako and her colleague detectives go to an area where a body was found. The case is presumed to be a suicide case, but the dead man is a suspect in an unsolved murder case. The man died in the same manner as the victim in the unsolved murder case.