Trial by Combat

A group of British aristocrats, who call themselves "Knights of Avalon", isn't content with the system of justice and executes judgment themselves. Instead of just killing the people they believe guilty, they give 'em a chance in traditional combat. When one day Sir Grifford witnesses their sessions, they have to remove him too. His son and heir, Sir John from America, starts to investigate with help from Ms. Marion and Colonel Cook from Scotland Yard. (imdb)