Marco encounters his ex-girlfriend Consueloand starts seeing her without telling that he has just married. Antonio is an MP and during his European trip he has a love affair with elegant Olga who has a big secret to hide. Recently-jilted Fabio is mistaken for psychiatrist by a beautiful girl Valentina with whom he falls in love. A divorce lawyer Sandra is romantically attracted to her client's husband Massimo.
Marco, Tato, Serena, and Leo are nine years old, and they are inseparable friends, ready to defend each other from their schoolmates’ bullying. On the evening of Marco's birthday, all four find themselves together to blow out the candles and unknowingly make the same wish: become adults. In one night's time, they find themselves magically the same age as their parents, but with the same behaviour and thoughts they have as kids.
