The drama which is based on the suspense novels "Kizoku Tantei" and "Kizoku Tantei tai Onna Tantei" by Maya Yutaka, features Aiba as a mysterious man who calls himself a noble but his name, age and background are all unknown and has an interest in solving cases but does not actually do the reasoning himself because he is more keen to talk to the women he meets at the crime scenes. Due to his status as a nobleman, he behaves very gentlemanly towards women and is unafraid of standing up against those in power. With the help of his servants i.e. driver Sato (Takito Kenichi), maid Tanaka (Nakayama Miho) and butler Yamamoto (Matsushige) who helps him to inspect the crime scenes and look for clues, he is able to assist the police in solving their cases with his strong observation power. Co-stars also include Takei Emi who plays Takanori, a newbie police detective at loggerheads with the nobleman while solving the cases, police detective Hanagata (Namase) who works with the nobleman at the orders of his superiors, Igawa Haruka who plays a female detective Kitami who teaches Takanori about detective work and is regarded as her idol and Nakama Yukie whose character details are not known at the moment.