Philadelphia resident Kevin Wendell Crumb suffers from Dissociative Identity Disorder. He speaks regularly with his devoted psychiatrist, Dr. Fletcher, who has already been able to distinguish twenty-three different personalities speaking in turn during their conversations. According to Fletcher, Kevin has suffered abuse and humiliation during his history and a 24th personality, darker and more menacing than all the others, named "the Beast", still remains buried. Dr. Fletcher emphasizes the fact that his patient forged these many different personalities in an existential need to protect himself from others. The situation is complicated when Kevin kidnaps three young girls.
