Series numeration from goodreads.com.

"Two years ago, FBI Agent Lucy Kincaid put psychopath Elise Hansen Hunt in juvenile detention for her role in an organized crime syndicate. Now eighteen, Elise has been released, and plans to take her revenge by making Lucy's life hell. The plot begins with Lucy's husband Sean Rogan, who has been arrested for a murder he most certainly did not commit. Lucy is determined to prove Sean's innocence, but is warned off the case by her boss. As she calls in reinforcements, she learns that Sean's brother Kane is missing in Mexico, her partner Nate Dunning has been arrested for possession of cocaine, and her friend Brad Donnelly has been kidnapped outside DEA headquarters."--Publisher.