What doesn't kill you / Iris Johansen.

Enhanced descriptions from Syndetics:

It's the deadliest poison known to man.

He's the only one who knows its true power.

She's the only one who can stop the evil.

The chase is on. . . .

Number-one bestselling author Iris Johansen showcases one of her most fascinating characters yet, pitted against one of the most ruthless killers, in a novel that will make you forget to breathe. . . .

Catherine Ling was abandoned on the streets of Hong Kong at age four. Schooled in the art of survival, she traded in the only commodity she had: information. As a teenager, she came under the tutelage of a mysterious man known only as Hu Chang---a skilled assassin and master poisoner. As a young woman, she was recruited by the CIA and now she is known as one of their most effective operatives. Having lived life in the shadows, Catherine is aware of the wobbly moral compass of her existence and even more aware of just how expendable she is to those she deals with. When her old friend Hu Chang creates a formula that's not only deadly but completely untraceable, the race begins to be the first to get it. With rogue operative John Gallo also on the hunt, Catherine finds herself up against a group so villainous and a man so evil that she may not survive in her quest to protect those she cares about: Hu Chang and Luke---the son who was stolen from Catherine and only recently brought home safe. Using all of her formidable skills, Catherine Ling proves the age-old belief that what doesn't kill you makes you stronger.

Iris Johansen is at her page-turning best in this novel that takes you from the corridors of Langley to the alleyways of Hong Kong and the darkest places of the human soul.