The eighth sister
(Book)

"Former CIA case officer Charles Jenkins is a man at a crossroads: in his early sixties, he has a family, a new baby on the way, and a security consulting business on the brink of bankruptcy. Then his former bureau chief shows up at his house with a risky new assignment: travel undercover to Moscow and locate a Russian agent believed to be killing members of a clandestine US spy cell known as the seven sisters. Desperate for money, Jenkins agrees to the mission and heads to the Russian capital. But when he finds the mastermind agent behind the assassination--the so-called eighth sister--she is not who or what he was led to believe. Then again, neither is anyone else in this deadly game of cat and mouse."--,Amazon.com