1914, Edendale, Los Angeles. Willie, a 16-year-old daredevil with a 4th-grade education, "presenting" (as present usage would put it) as a young woman, burns down her family farmhouse and seeks out Mack Sennett's Keystone lot, the first major "studio" in L.A. Finding her adept at feats of derring-do, Mr. Sennett employs her to do same in Keystone's one- and two-reel comedies alongside the likes of Mabel Normand, Roscoe Arbuckle, and Charles Chaplin...