A city on edge as a serial killer roams the streets. Frustrated by one unsolved murder after another, forensics graduate student Rei Kuroshima decides to get his hands dirty to solve the crimes. He resolves to copy the killings to chase the serial killer known as "The Doctor" in order to figure out how the murders were accomplished. Along the way, he begins to develop certain... urges. Accompanied by his supervisor Aiden Steele, a detective oblivious to Rei’s identity as the copycat killer, he must piece together a trail of evidence to uncover the identity of “The Doctor.” At school, however, Rei must also maintain his normal student life while dealing with his desire to kill, leading him to the ultimate choice - Who will he choose to love, and who will he resolve to kill?