A Highwayman Came Riding (a Regency Romance‪)‬

The Duchess of Bixley, owing to her nipcheese ways, was traveling late near London so she might save the cost of an inn. What it cost her was her diamond necklace, taken by the highwayman "Captain Jack." So milady faked a heart attack, and her faithful companion, Marianne Harkness, was given the task of recovering the booty--and reforming the villain.  Regency Romance by Joan Smith; originally published by Fawcett Crest