In LOCKED ON, written in collaboration with author Mark Greaney, Clancy's electrifying thriller finds his greatest characters facing their greatest challenge when John Clark becomes the subject of an international manhunt. The explosive action takes readers from the United States and France to Egypt, Dubai and Pakistan.§Jack Ryan, Sr. has made a tough choice. He's running for President of the United States and giving up a peaceful retirement to help his country in its darkest hour. But he doesn't plan on the perfidy of his opponent who uses trumped up charges to attack one of Ryan's closest comrades, John Clark. Now, Clark engages in a desperate struggle across three continents. He must travel the world, staying one step ahead of the authorities, and a shadowy organization tasked to bring him in, all while trying to find the man who fingered him for a crime he never committed.§Meanwhile, the Campus, the top secret off-the-books intelligence agency, faces its most implacable foe - a renegade Pakistani general who plans to unleash a wave of terror that will restore the Caliphate. With John Clark missing, Jack Ryan, Jr., Ding Chavez, and Dominic Caruso must race against the clock to foil.