In apertura di serie, Mason Kane e Nadia Sinh, dell’agenzia di spionaggio indipendente Citadel, si scontrano con una diabolica nuova organizzazione, Manticore, che porta Citadel alla catastrofe. Otto anni dopo, Kane vive una vita tranquilla da “Kyle Conroy”, senza memoria del passato. Finché, un giorno, un ex collega gli chiede aiuto per impedire a Manticore di creare un nuovo ordine mondiale.

Il viaggio di Kyle e Bernard a New York per rubare la Valigetta X di Citadel dal Quartier Generale di Manticore prima che sia troppo tardi. In seguito, Kyle apprende che un personaggio del suo passato è ancora vivo e rischia il tutto per tutto per trovarlo.

As Kyle and Nadia land at an old safehouse, small clues about their past life together bubble to the surface. Soon, they discover a former ally who may be key to stopping Manticore is imprisoned in a facility in Morocco. In order to rescue him they first have to enlist the help of a local crime boss. But their mission is compromised as secrets of the past are unearthed.

After the shocking revelation of Abby’s former identity, we learn of the past entanglements between Mason, Nadia and Celeste, and a horrific decision that reverberates still today. Meanwhile, Nadia and Kyle land at the Manticore compound in Morocco and risk their lives to free their fellow spy. But their hero’s welcome is short-lived as they are forced to grapple with a dangerous accusation.

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.