Okay, so Secrets of a Lady by Tracy Grant isn't a shoot 'em up book, but there was shooting and plenty of action (and drama).
Evidently this book was published first as Daughter of the Game, which made at least one Amazon reviewer upset. The story follows Melanie and Charles Fraser, who's son is kidnapped and held for ransom. Except the ransom is a special, historical ring that the Frasers don't have--but they do have a connection to the ring. The book follows their journey to save their son.
It took me quite awhile to get into the book; I almost quit it several times. But after Melanie reveals her big secret (hence the "secrets of a lady"), I was more interested.
The action happens quickly, there's plenty of tension between the two leads, and numerous twists. While it's not suspenseful, it's still full of continuous action. The writing was good, too, for a debut novel. All in all, I ended up liking it just fine.