Sakaguchi plays the lead character Saegusa Kento, a police officer who manages to connect to another police officer living in the past through a disposed walkie talkie and the two of them work together to crack unresolved cases. Saegusa works at Josai Police Station and learnt criminal profiling on his own. When he was a child, there was a kidnap-cum-murder case involving his classmate and his elder brother committed suicide due to a past case. This led Saegusa to be scarred emotionally and he has a deep distrust for the police even though he became a police officer to find the truth behind his brother's death.
Kitamura Kazuki plays the police detective Ooyama Takashi who connects to Saegusa from the past through the walkie talkie. Although he is a righteous police detective who would never go against his principles, he disappears without a word suddenly after being suspected of receiving bribes. Kichise Michiko plays Saegusa's colleague-cum-partner Sakurai Misaki who is a cool police detective and used to train under Ooyama when she was a newbie. Last but not least, Watabe plays Nakamoto Shinnosuke, the director of the criminal investigation unit in Metropolitan Police Department who holds great power and is known for his unfeeling and cruel ways when concealing the evil deeds of politicians and huge corporations.
Kitamura who had worked with his co-stars before, commented that he was glad to be able to engage in some intense acting with Watabe again after a long time. As for Sakaguchi and Kichise, they were playing characters with very different relationship links the last time they worked together as compared to this drama so he would be glad if they could make the viewers accept their "new" relationships onscreen. As for Kichise, she expressed her joy to be able to work with a popular actor like Sakaguchi and that Kitamura who is like her elder brother, would be around to help her as well. As for Watabe, she always thought of him as one with a dandy image even though he was quite different on variety shows so she felt that it would be interesting to work with him.
Watabe commented that he had watched the original drama and praised it to be a wonderful piece of entertainment. As such, for him to be able to participate in this drama, he was very thankful about it and looked forward to making the Japanese version an even better one than the original.