Merciless
He's an FBI agent; she's his executive assistant (don't ask her to make the coffee). He is rich; she is just getting by. She has an illegitimate son; he's the father but doesn't know it. They are trying to track down the killer of his brother's first wife and child. A little repetitious which may be fixed before the final book is done but the usual Palmer romance with nice bantering between the guy and the girl.