Michelle Gagnon 
Gatekeeper [EPUB ebook] 

From the moment sixteen-year-old Madison Grant is abducted, an unthinkable terrorist plot is set in motion-pitting Special Agent Kelly Jones against her most powerful adversary yet.The kidnapper’s ransom demands aren’t monetary…they come at a cost that no American can afford to pay. As Kelly’s fiance, Jake Riley, races to find Madison, Kelly is assigned to another disturbing case: the murder and dismemberment of a senator. At first the two cases don’t appear to be related.But as Kelly navigates her way through the darkest communities of America-from skinheads to biker gangs to border militias-she discovers a horrible truth. A shadowy figure who calls himself The Gatekeeper is uniting hate groups, opening the door to the worst homegrown attack in American history.