Each of the four have no authority to investigate nor make any official claims, but each have their own personal reasons for pursuing the clues to get down to the real truth of the matter!
Haruhi Mabuchi (Taiga Nakano) works for General Affairs and is an affable and easygoing guy. He is eternally optimistic and turns any negative thing into something positive, and it is through his his friendliness and energy that the team eventually connects-
There is Ruka Kotori (Tasuku Emoto), a brooding and morose guy from Accounting, who, though having no real interest in the current case (about a young boy suspected of leaping to his death at a hospital), wants to solve it as a favor to a detective named Hattori.
It seems this Nagisa Hattori (Yui Sakuma) is the only one on the official investigative team who truly cares about the victims and solving the case, however she is picked on and constantly put down by the other members of the investigative team. But Kotori sees her passion and is irked by how the superiors treat her.
“Wouldn’t it be great if we could solve this and tell Hattori so she could get the credit?” Kotori thinks, and decides to enlist the weak-willed Mabuchi into helping him snoop around and dig up the facts.
"Please, someone may be in danger if we don't investigate this lead!" she pleads.
But the head officers (Ryosuke Mikata and Catherine Seto) just brush her off.
A recently suspended detective named Suzunosuke Shikahama (Kento Hayashi) has been holed up at home, spying on his neighbor whom he suspects is a serial killer. Shikahama laments that he only became a detective because he thought it would be like TV, chasing killers and solving locked room murders, instead all he gets is orders to check license plates, etc. How he would love to work on an actual TV-type mystery, and so he is the first one Mabuchi thinks of calling when he and Kotori come to a dead end!
Though reluctant at first, the theatrical nature of the case woos him and eventually Shikahama is on board, analyzing the clues they bring him and giving theories.
And finally, there is the tuff as nails Sesuna Tsumiki (Mayu Matsuoka), she of the Community Safety Department. When Mabuchi and Kotori are sneaking into the evidence room at night to peek at the files, they find the intrepid girl already at the box! Seems she also suspects foul play at the hospital and has been investigating things on her own. When they realize they have the same mission, they decide to pool their efforts. 
Thus the unofficial team is born and, under the instruction of Shikahama to discard what they see and "use their third eye to see only the truth", the group gamely tackles the murder mystery and don't stop until they have come up with the solution!
Having so much FUN watching this one- such wonderful dialog between the principle characters, and I was not surprised when I looked up screenwriter Yuji Sakamoto and found he was the same writer of other dialog-heavy dramas like "Quartet" and the recent Takako Matsu drama "Omameda Towako to Sannin no Motootto", both dramas I REALLY loved!!
Can’t wait to see more!
PS: What is it with these pretty girls donning these bad wigs lately? First we had Fuka Koshiba in Kanojo wa Kirei Datta, then Mio Imada in Waru, and now we have Yui Sakuma with another ill-fitting hairpiece!
She's still as wonderfully charming as ever, but this is a very weird trend.
