It starts with the unthinkable: a horrifying act of terrorism on American soil.

Only one man can stop them. Code name Devlin, he exists in the blackest shadows of the United States government - operating off the grid as the country's top agent. He is their most lethal weapon . . . and their most secret. But someone is set on drawing him out into the open by targeting America's citizens, the people Devlin is sworn to protect - and they will continue the slaughter until they get what they want.