A bizarre, but bloody serial murder case takes place. The murders seem to be influenced by the picture book "Kaibutsu no Kikor." The serial killer wears the mask of the "Lumberjack Monster" and attacks his victims' with an ax to take their brains. The serial killer's next target becomes the lawyer Ninomiya Akira. The lawyer is unusual in that he lacks empathy for others. He is also a cold-blooded and heartless person and carries the traits of a psychopath. Other people become involved in the case including profiler Toshiro Ranko, Ninomiya Akira’s fiancée Hasumi Emi, Dr. Sugitani Kuro and past murder case suspect Kenmochi Takeshi. The case needs to be solved like a puzzle, including finding out why the serial killer takes the victim's brain and why the next target was chosen. Ninomiya Akira must work to solve this puzzle to save his own life.