Locked On is a techno-thriller novel written by Tom Clancy and Mark Greaney released on December 13, 2011. A direct sequel to Dead or Alive (2010), it is Clancy's first of three collaborations with Greaney and features Jack Ryan Jr. and The Campus as they try to avert a nuclear threat from a rogue Pakistani general, as well as his father Jack Sr. in his presidential campaign. The book debuted at number two on the New York Times bestseller list.

Plot summary (abridged)

A year after the Emir's capture, The Campus investigates Pakistani intelligence official and brigadier general Riaz Rehan. Unbeknownst to them, Rehan plots to bring his country and India to nuclear war by orchestrating terrorist attacks behind the scenes on behalf of terror groups allegedly backed by the Pakistani government, aiming to create an Islamic caliphate in its aftermath. For the final step of his operation, he steals two nuclear weapons from the Pakistani military armory and then secretly gives them to Dagestani terrorist organization Jamaat Shariat, who would then use them to attack Moscow using space delivery rockets.

Meanwhile, former president Jack Ryan is in the middle of his presidential campaign and ahead at the polls. Even though his opponent and successor Ed Kealty publicly reveals the capture of the Emir in their second presidential debate in a desperate attempt to win voters, Ryan opposes his plan to a public trial for the terrorist. The resulting turnaround in public opinion enrages Czech billionaire and Kealty supporter Paul Laska, later launching a vendetta to discredit Ryan six weeks before the presidential election.

Laska's progressive organization provides the Emir with a legal defense team. After CIA deputy director Charles Sumner Alden identifies Campus operatives John Clark and Domingo "Ding" Chavez from the Emir's rough sketches of the men who captured him, Laska enlists the help of SVR officer Valentin Kovalenko for collecting information about the former's CIA activities. Kovalenko uncovers Clark's unauthorized assassination of an East German Stasi operative in Berlin in 1981, which is not part of the full presidential pardon Ryan had signed for his friend and making him accountable for murder. Laska covertly gives the dossier to Kealty, who then orders the FBI to hunt down Clark.

Locked On is an exciting book written by Tom Clancy and Mark Greaney. The story is filled with suspense and action, keeping readers engaged from start to finish. With its gripping plot and well-developed characters, Locked On is a must-read for fans of the thriller genre.