In 1900, Roberto Colombo, an Italian-American attorney living in the
Little Italy section of New York City, is killed by gangsters as he meets with a police officer to divulge information about an extortion attempt. His widow and son return to Italy, where his widow dies. In 1908, his son Giovanni Colombo returns to New York, determined to wage a vendetta against the men who killed his father. He meets with childhood friend Isabella Gomboli and police detective Louis Lorelli, who try to dissuade him. Roberto talks to a man whose son was kidnapped after he had refused to pay
protection money to the mob. A man whom Giovanni had hoped would tell him about his father's killers is murdered. Giovanni and Isabella work to rally people in Little Italy against the Black Hand racket, but the movement is dealt a setback when Giovanni is attacked and his leg is broken. Recovering from his injury, Giovanni resolves to study law as his father had, with the help of Isabella, with whom he has fallen in love. When Lorelli shows them evidence uncovered after a bombing of a local store, Giovanni delays his studies to help find the perpetrators. A court trial comes to nothing when a key witness is intimidated and refuses to testify, but the defendant is deported when police in
Naples identify him as a fugitive from justice. Following the deportation, Lorelli travels to Italy to examine photographs of Italian criminals who are at large, hoping to identify other New York gangsters who could be deported to Italy. After he has mailed a list with the results of his research back to Giovanni in New York, Lorelli is attacked and killed. In an attempt to prevent Lorelli's list from reaching the authorities, gangsters kidnap Isabella's young brother. Giovanni is captured while trying to save him and reveals the location of the list to the gangsters after they threaten to cripple the boy. After the gangsters acquire the list and the boy is released, Giovanni escapes and saves the list by igniting a bomb that he finds in the gangsters' hideout. ==Cast==