Sidney Sheldon. If Tomorrow Comes 2

…The family happiness of Tracy and her partner in crime, the irresistible gentleman thief Jeff Stevens, was short-lived. Their new life, where there's no more room for dangerous adventures, seems bland and empty to Tracy. But when one day Tracy disappears without a trace, Jeff understands: he must find and bring her back at all costs. Even if it means risking his own life and entering into a duel with very dangerous people from the world they once were a part of alongside Tracy…