On a flight, Sister Bertrille suddenly gets dizzy and has double vision, forcing a crash landing. After being checked out by Dr. Tapia, he discovers she has an ear infection that will clear up in a couple of days. He is more concerned about the condition of the Reverend Mother. She is a bit anxious about Sister Bertrille in general but more so now with Sister Bertrille's ailment. The doctor however attributes the Reverend Mother's anxiety to work stress and thus calls in Father Lundigan, the church's psychologist, to allay the Reverend Mother's anxiety. The Reverend Mother makes the mistake of telling Father Lundigan that the source of her anxiety is the flying nun, or rather the landings of the flying nun. The father promptly thinks the Reverend Mother is going crazy. Perhaps it's something in the water at the convent Sister Jacqueline and Sister Bertrille herself support the Reverend Mother's story. The only way to convince Father Lundigan is for Sister Bertrille to fly for him. However her ear infection is causing Sister Bertrille to be grounded. One by one, all the sisters support the Reverend Mother's story. Father Lundigan thinks he's surrounded by a convent full of deranged nuns, this further supported when the sisters try everything in their power to keep the father at the convent until Sister Bertrille's ear infection clears and she can fly again for the father. Father Lundigan manages to "escape" from the convent just as soon as Sister Bertrille's infection clears and she's able to fly again. Sister Bertrille finally manages to convince Father Lundigan when she flies next to the airborne plane which he's aboard. Or perhaps she's only convinced him that he's as crazy as all the nuns at the convent.
—Huggo