On the eve of the new millennium, Dr. Jekyll conducts successful scientific experiments with laboratory animals, including a giant ape. However, his scientific achievements lead him to test the serum on himself, resulting in disastrous consequences. Although his heart is cured, he suddenly feels his cells transforming into a monstrous and primitive shadow of himself, known as Mr. Hyde. Dr. Jekyll becomes a paranoid schizophrenic, plagued by various mental illnesses. He fails to realize that Mr. Hyde is a reflection of himself, a monster residing deep within his soul, causing chaos and destruction.