Casey is attacked at random on the street and enlists in a local dojo led by a charismatic and mysterious Sensei in an effort to learn how to defend himself. What he uncovers is a sinister world of fraternity, violence and hypermasculinity and a woman fighting for her place in it.

Jeffrey Dahmer struggles with a difficult family life as a young boy. During his teenage years he slowly transforms, edging closer to the serial killer he was to become.