Amagi Yu and Katagiri Masatoshi have become subordinate and boss in the Criminal Documents Unit while Mizuta Tamaki and Aoyama Arata remain detectives in the Twelfth Section under the instructions of Katagiri. Together with professor of forensic medicine Domoto Shuntaro, veteran senior detective Ebisawa Yoshiki in the Twelfth Section and newbie Nonomura Takumi who is Amagi's subordinate, the seven of them take on old unsolved cases. (Source: wiki.d-addicts)