Chi sei?

Jessica Barrett (Juliet Mills), a young English mother living in San Francisco, reveals to her music executive husband, Robert, that she is pregnant. The couple already have two young children: a son, Ken, and daughter, Gail. As Jessica's pregnancy progresses, she exhibits violent mood swings, apparent hallucinations of voices, and poltergeist phenomena, including levitating into the air. Dr. George Staton, her obstetrician and personal friend, confides in Robert that Jessica's pregnancy is progressing at an unbelievably rapid rate, and her behavior becomes increasingly horrifying, akin to demonic possession. Robert is contacted by a mysterious man named Dimitri, who instructs him to sequester Jessica in their house and keep visitors away, in order to assure that the child is born.