According to Sir Sidney Colvin, quoting Stevenson's stepdaughter, Stevenson intended the story to continue with the seduction of (young) Kirstie by Archie's dissolute friend Frank Innes. Kirstie's four brothers believe that Archie is the culprit and vow revenge on him. However, Archie has meanwhile confronted Frank and killed him, and is arrested for murder. He is tried for his life before his father (this is legally implausible, as Weir Snr. should have recused himself from presiding) and condemned to death. But the older Kirstie discovers the truth and tells the brothers, who break the jail and release Archie. Archie and his beloved Kirstie flee to America, presumably to live happily ever after.
