The Bonotti are an old couple ,from a modest background.They had their daughter Mariella brought up in a luxury secondary school, outside Roma, where she has grown up without knowing her parents are actually rather poor.They learn her hand was asked by a wealthy financier's son.The wedding is arranged for the next month.When she discovers her parents' house,Mariella bursts into tears,for she knows her fiance will break up when he he sees his future in-laws' modest situation.Bonotti makes a big decision: he will transform the apartment,should he ruin himself in the process.