[The following plot summary is based on the English language version of this film, The Trial of Mary Dugan ; character names refer to that version.] Pretty Mary Dugan is placed on trial for the murder of her sugardaddy, who was found shot to death in the apartment he kept for her. Edward West, Mary's attorney, deliberately restrains himself in his cross-examination of the witnesses for the prosecution, and Mary's brother, Jimmy, who is a fledgling lawyer, strongly protests. West withdraws from the case, and Jimmy takes over his sister's defense. Jimmy puts Mary on the stand, and her subsequent testimony reveals that she had been the mistress of four successive men in order to earn enough money to put Jimmy through law school. Jimmy brings about Mary's acquittal by proving that Edward West was the man who murdered Mary's benefactor.