When Buster Keaton first screened his 1925 silent comedy Seven Chances for a test audience, he knew something was wrong. The story of a man set to inherit $7 million if he is married by 7pm on the eve of his 27th birthday, the film built to a terrific image: 500 would-be brides, chasing our tortured hero through the streets of Los Angeles. Keaton’s escape leads him to a rocky...