Esperanza (Angelica Maria) is a young novice living in a quiet convent full of old nuns. After eating some "special" mushrooms, innocent Esperanza becomes modern and psychodelic Brenda: a subversive girl who raids a high-society party, sings subversive songs and charms young fellows. Brenda and five boys leave the party, assault an ice-cream parlor (they ask for "five of chocolate and one of strawberry") and finally kidnap a banker. In between, a Commissioner from the Surveillance International Agency follows Brenda's tracks, while the girl changes personalities due to the mushroom eating.