The Cup of Fury is a 1920 American silent drama film directed by T. Hayes Hunter and starring Helene Chadwick, Rockliffe Fellowes, and Frank Leigh.

He meets their adopted daughter Marie (Chadwick) and recalls having seen her before in America, where she was billed as "Mamsie" in a vaudeville act.

That evening Scotland Yard's secret service men raid the Weblings and their daughter, whereupon she confesses that she is an American and is allowed to return to the United States.

The secret launching of a ship is innocently disclosed by Mamsie to her brother-in-law, a confessed member of the Industrial Workers of the World, who in turn advises a German spy.

Mamsie then proposes to run down the criminals and, while employed as a "passer boy," unearths a scheme to blow up the dockyards.