The Second Investigation Department is a neglected place in the Metropolitan Police Department. Although it has the title of "specially responsible for handling long-pending cases", in fact, everyone in the department is just slacking off. Until one day, a top student from the University of Tokyo, Jun Shibata (played by Miki Nakatani), joined. Jun Shibata has rare calculation and analysis abilities, and the process of solving the case is thrilling, but on the other hand, she is a very simple life idiot. Her colleague Mayama Tetsu (played by Atsuro Watanabe) is her partner and nanny, taking care of the offline Shibata. Mayama carries a heavy past. Seven years ago, her sister was gang-raped, but the murderer was never caught. Shibata began to re-investigate the incident, but found that all the confusions in the past were intertwined, and he could not get rid of this fog...