An Improper Companion. Anne Herries

Daniel, Earl of Cavendish, finds the frivolity of the ton dull after the adventures and hardship of the Peninsular War.But boredom rapidly disappears when he's drawn into the mystery surrounding the abduction of gently bred girls. His investigation endangers his mother's new companion, Miss Elizabeth Travers. Although she is tainted by scandal, her cool and collected response commands Daniel's respect–while her beauty demands so much more.