The life of Paolo (Marcello Mastroianni), a quiet and indolent taxi driver, is turned upside down when he meets Lina (Sophia Loren), a beautiful girl, skilled in pickpockets and petty scams. Lina and her family, disjointed like her, fascinate Paolo who does all he can to redeem the girl. With Vittorio De Sica in the role of Prof. Stroppiani, Lina's father.