Tamayama Tetsuji plays the role of Muto Takashi who is a former police detective using illegal methods to solve cases which are difficult to handle by the police while Tanihara Shosuke plays Muto's buddy and a police detective Kaburagi Wataru and Watabe Atsuro plays Tamaki Keigo who takes charge of the special missions given to Muto. While exploring the lives of these men, the topic of whether revenge is right or wrong is discussed in this suspense drama.
In Season 1, it features the story of how Muto's younger sister was killed by an underaged person and didn't get his due punishment. Although he had the urge to take revenge for his sister, the murderer suddenly committed suicide. Muto realised that this frightening trait in his character which could bring him over the edge and decided to quit being a police detective. One year later, he starts to take on cases from the police assigned by Tamaki which they are not in a convenient position to handle. Season 2 describes how Kaburagi who used to date Muto's sister gets trapped by the consequence of his decision to take revenge and how he and Kaburagi clash over their views about revenge as well as how this leads to a tragic ending for them.