The Gentleman Thief: Harlequin comics

Georgiana, the daughter of a wealthy family, wants to become a famous detective more than anything. She’s looking forward to this summer’s vacation. Something is sure to happen at the popular resort in Bath where the aristocracy and the wealthy are gathering. Then, amid their endless parties, a famous emerald necklace is stolen! Georgiana, who just before the crime overheard a mysterious conversation, begins investigating at once. But the enigmatic and handsome Marquis of Ashdowne keeps popping up wherever she goes. Now he suddenly wants to be her assistant!