The Telephone Girl (1927)

Political boss Jim Blake, supports his son-in-law, Mark Robinson running for governor. They discover that Robinson's opponent registered in a hotel as "Matthew Standish and wife" three years before his marriage. Blake traps Standish into attempting to warn the girl in question of this discovery, but Kitty, a telephone operator important to their scheme, refuses to cooperate. Eventually the facts are sorted out, and Kitty marries Blake's son, Tom.