An interesting blend of African spiritualism and demonic possession, Abby is the story of a minister's wife possessed by an ancient African demon. Abby's father-in-law, archaeologist bishop Dr. Williams (William Marshall) is in Nigeria, researching and documenting facets of the Yoruba religion. While excavating a network of caves, Williams comes across an ancient idol. In the process of excavating the site, he accidentally releases Eshu, god of sexuality, from a phallus-shaped box. The demon finds its way from Nigeria to Louisville, Kentucky, the home of Emmet and Abby Williams (Terry Carter, Carol Speed).