Mister Joaquim Pelletier and his wife request the services of the private detective Pepe Carvalho to find the murderer of their only son, Mariano. As the investigations progress, Pepe finds out that Mariano was not such a model son as his father thought. He had a double life: a banker at daytime, a thug at night; he was cooperating with Jesús Arquimedes, the boss of the underworld, by doing illegal works for him. But Mariano had decided to betray Arquímedes, embezzling $500 000 of the money he was laundering in Bank Pelletier, to start a new life in the USA. Arquímedes puts pressure on Carvalho to find his money. Surprisingly enough for the detective, the guilty one is not Arquímedes, but the father of Mariano. Mister Jaoquim had a passionate relationship with his son since childhood, he wanted to mold his son as he had always dreamed, and never admitted that Mariano was someone different and a rebel who wanted to run away from Barcelona for ever.