This novel is Catherine Ling's story. For those of you who are regular readers of Johansen, you'll know exactly what that means. If you know who Catherine Ling is, this is a great book. If you are unfamiliar with Catherine, I'd suggest you read Bonnie and/or Eve first.
Catherine is working at creating a home for and building a relationship with her son, Luke. But, her CIA ties still bind, and her old friend Hu Chang is the one in trouble. Hu Chang is a master potion maker - his creations can cure and kill and more. The leader of a ruthless organization has learned that Hu Chang can create a poison that can kill and leave no trace - the perfect weapon for assassination. This evil man wants the potion and will use every twisted and violent means at his disposal to get it. He has shanghaied Hu Chang and the CIA wants him back. They rescue him, but he slips away from them. They call in Catherine to get him back again.
As Catherine flies from Virginia to Hong Kong, she remembers her childhood and her first encounter with Hu Chang. This flashback gives us a good look at Catherine's formative years and her only relationship as a child.
She tracks down Hu Chang, and they go after the bad guy. She hooks up with John Gallo again as he is the CIA's resident expert on the man they are chasing. The three of them clash, as all are accustomed to being in charge, but they eventually get their man. And, find out that what doesn't kill you really can make you stronger.
See my reviews of Eve and Bonnie.