Dr. Jekyll believes good and evil exist in everyone and creates a potion that allows his evil side, Mr. Hyde, to come to the fore. He faces horrible consequences when he lets his dark side run amok.

Having once again avoided criminal conviction, Professor Moriarity develops a murderous plan to “finish off” his last major nemesis, Sherlock Holmes, by making him fail to prevent the perfect crime. Does it involve a family curse, the crown jewels of England, or something else…

A young woman, Jill Young, grew up on her father's ranch in Africa, raising a large gorilla named Joe from an infant. Years later, she brings him to Hollywood to become a star.