Madam Who? (1918)

Jeanne Beaufort becomes a secret service agent for the South during the Civil War, to avenge the deaths of her father and brother. While eavesdropping on a meeting of Northern spies, she is captured and forced to wed a masked man who bears a peculiar tattoo on his wrist. Jeanne escapes and soon afterwards, continues her work in Washington, D.C. with the aid of Henry Morgan, who, unknown to Jeanne, is a Northern agent. In Washington, she unwillingly falls in love with John Armitage, a Northerner. In procuring a set of important documents, Jeanne's identity is discovered, and she is forced to escape to Richmond. Morgan, who is revealed as Jeanne's mysterious husband, is killed in a struggle with "Parson" John Kennedy. Richmond is set ablaze, but John rescues Jeanne, and after the war, they forget their differences and marry.