Rookie detective Tatsuya Sumire has dreamed of being like the hot-blooded detectives who appear in detective dramas since childhood. However, he is assigned to the First Section of Tokyo Metropolitan Police Department’s Special Entertainment Division, a section which deters crime of influential entertainers. The first order Tatsuya gets from his superior is to infiltrate an internet TV’s music programme as an idol in order to investigate a threatening letter. And so, the five-member idol group ‘Deka Dance’ is formed impromptu with Tatsuya, one-time swindler Kurosawa Yuya, former recluse Sakai Shokichi, struggling child star Hoshi Teruo and a silly part-timer Degawa Tetsuya. They are initially bewildered by the special world of the entertainment industry and keep getting into conflicts, but somehow get popular each time they investigate and solve the challenging cases that occur daily. And then they gradually become aware of themselves as idols. However, they will soon have to face off against the mysterious consummate villain.