Penny finds a large mirror on the planet that is the door to a strange world inhabited by a boy who has access to all the existing mirrors in the universe, accidentally Dr. Smith also enters this surreal world but when he leaves he tries to destroy the mirror. Mirror, ignoring that if she does, Penny will be trapped inside forever. The episode has a lot of metaphor, Penny is going from her childhood to the stage of adolescence, this confuses her since deep down she refuses to grow up, the boy inhabitant of the mirror symbolizes the reflection of the feelings of confusion for which she She is going through, and finally we see her accepting to leave behind her stage as a girl to gradually become a woman.