From Shinmakoku Scanlations :

Koga Masataka and Terajima Ryuji are homicide detectives working for the police department. Behind the stoic facade, Koga is suffering from the pain of his past. When Terajima blatantly opens his heart to him, Koga is left confused. While behind closed doors they are more than "office partners", Koga is still afraid to let himself believe that he could be what Terajima wants him to be. It's a love story between a Tough man and a Smart man trying to understand each other as they finish one murder investigation after another.