Series numeration from Fantastic Fiction.

"What became of Mitch and Abby McDeere after they exposed the crimes of Memphis law firm Bendini, Lambert & Locke and fled the country? The answer is in The Exchange, the riveting sequel to The Firm, the blockbuster thriller that launched the career of America's favorite storyteller. It is now fifteen years later, and Mitch and Abby are living in Manhattan, where Mitch is a partner at the largest law firm in the world. When a mentor in Rome asks him for a favor that will take him far from home, Mitch finds himself at the center of a sinister plot that has worldwide implications--and once again endangers his colleagues, friends, and family. Mitch has become a master at staying one step ahead of his adversaries, but this time there's nowhere to hide."--