The Runaway Heiress by Anne O'Brien

Frances Hanwell effects a daring night-time escape - in the Marquis of Aldeborough's carriage! Mistaking her for a servant, Hugh only realizes his error the next day. With scandal imminent, a reluctant marriage seems the only course of action. Reluctance turns to respect when Hugh uncovers the brutal marks of her unhappy life. Now, he will do anything to protect her . . .