Nora and Martain never greet or give thanks, but one day they realize that their lack of etiquette is rendering them invisible.

Elisenda Roca is an award-winning Spanish radio and television journalist who has served as the doyenne of the Association of Journalists of Catalonia. She is the author of several books for parents and parents-to-be. Cristina Losantos is an illustrator who regularly contributes to newspapers and children's magazines. She is the illustrator of a set of books in the Caballo alado ACCIÓN series. They previously collaborated on the children's books ¡Fuera pesadillas! and ¡No somos los tres cerditos!