Matilde is a nun convinced that faith moves mountains. She secretly begins a mystic fasting to end what she considers to be the second great flood. Elena is a thin and fashion-conscious woman ashamed of her daughter's chubbiness. She's willing to do the impossible to make her daughter Linda thin so Linda will look like a little princess on the day she receives her first communion. At the same time Elena's husband Gustavo - a professor of architecture - cannot cope with his wife's bones poking him during intimate moments so he turns his attention to a buxom female student with a hearty appetite.

Matilde, que ha dejado la medicina para ingresar como novicia en un convento, realiza secretamente un ayuno místico para terminar con lo que considera un segundo diluvio, mientras prepara a su prima Linda para la primera comunión. Elena, la madre de Linda, es una mujer obsesiva y delgada hasta la exageración, se avergüenza de que su hija sea gordita, y hace hasta lo imposible por adelgazarla. Mientras tanto, Gustavo, el papá, descubrirá el amor gracias a la Gordibuena, una alumna amante de la buena comida.