"Glen or Glenda" tells two stories. One is about Glen, who secretly dresses as a woman but is afraid to tell his fiancée, Barbara. The other is about Alan, a pseudohermaphrodite who undergoes a painful operation to become a woman. Both stories are told by Dr. Alton, who also delivers an earnest lecture on tolerance and understanding. There is a second narrator, called the Scientist, whose commentary on the action contains more philosophical pronouncements than facts. The movie also has flashbacks-within-flashbacks and a strange dream sequence. We meet Insp. Warren, whose investigation of a transvestite's suicide leads him to learn more about men in women's clothes; Johnny, whose wife left him when she discovered what he wears when she's away; Barbara, oblivious to Glen's desire to wear her angora sweater; Satan, who invades Glen's nightmare; and others. Meanwhile, the Scientist will only offer cryptic advice. "Beware!" he warns. "Beware of the big, green dragon that sits on your doorstep. Beware! Take care! Beware!"