 Sister Bertrille needs to see Dr. Paredes, the dentist, to have a toothache fixed, but Sister Bertrille is scared of dentists. So the Reverend Mother goes with her to hold her hand. To calm Sister Bertrille s nerves, Dr. Paredes puts her under hypnosis. However the Reverend Mother accidentally gets hypnotized at the same time. Fascinated by this, Carlos wants to see the results of the hypnosis, and as a lark, Dr. Paredes gives them a post-hypnotic suggestion: every time they hear the word "red", Sister Bertrille will act like the Reverend Mother and the Reverend Mother will act like Sister Bertrille. It works. Before Dr. Paredes needs to rush off, he fixes Sister Bertrille s tooth and brings both women out of hypnosis. However he forgets to remove the post-hypnotic suggestion. Unfortunately, this act coincides with Father Lundigan s visit to the convent, Father Lundigan the church s psychiatrist. Last Father Lundigan visited, he had a year of therapy since all the sisters tried to convince him that Sister Bertrille could fly and he thought he imagined Sister Bertrille flying outside his airborne airplane (it actually was her). Father Lundigan says "red" in front of the women, and they start acting like each other. The worse part about it is that the Reverend Mother believes she can fly as she is acting like Sister Bertrille. Father Lundigan thinks the sisters are once again going crazy and quickly rushes off back to the mainland to provide his report as such to the bishop. Just as Father Lundigan leaves, Dr. Paredes arrives to take the post-hypnotic suggestion off. Once back to their own selves, Sister Bertrille finds out from Sister Jacqueline about Father Lundigan s visit. The only thing Sister Bertrille can do to convince the Father that she can fly is to fly up to his airborne airplane, which she does. Father Lundigan sees her outside the plane, and once again will have to undergo more therapy himself.