One Hour Before Dawn (aka Behind Red Curtains) is a 1920 silent film mystery directed by Henry King, written by Fred Myton and starring H. B. Warner, Frank Leigh and Anna Q. Nilsson. It was produced by Jesse D. Hampton and released by Pathé Exchange.

Anna Q. Nilsson emigrated to Hollywood from Sweden in 1910 to become a silent film actress, but failed to make the transition to talkies. She made a total of 200 films., almost 50 of them sound. She never completely recovered from a fall from her horse at the beginning of the 30s, but was always in demand for smaller parts, among them Sunset Boulevard and Seven brides for seven brides, her last in 1954. When she died in 1974 several American television stations interrupted their programme to show clips from her films