Mason Kane and Nadia Sinh – top agents of the independent spy organization Citadel – collide with a nefarious, new syndicate – Manticore – leading to catastrophe. Eight years later, Mason Kane is living a quiet life as "Kyle Conroy," with no memory of his past. Until one day an old colleague enlists his help to stop a now powerful Manticore from creating a new world order.

Nadia, Kyle and Carter are forced to work together to escape from Manticore and protect the X Case, but suspicion of one of our heroes reaches a boiling point, leading to an explosive reckoning.

With one of their own being held hostage by Manticore, Kyle, Nadia and Carter risk everything to save them and thwart Manticore’s plans to acquire nuclear weapons. As our heroes grapple with the nuclear threat, the identity of the mole within Citadel will be revealed, as will the awful truth that everything they know is a lie.