Martin, Crystal and Troy Buchannan go undercover when a chemistry teacher and his family are kidnapped. The case takes on urgency when it's feared the kidnappers will use the teacher to manufacture a deadly gas.

Martin poses as an international arms dealer to rescue kidnapped chemist Richard Hubbard and track the sale of VX gas. Before long, he connects with a beautiful arms trader and slips into a shadowy romance with her.

Martin is sold VX gas, resulting in the apprehension of the Colonel and Ana Paulanos. In response, one of the Colonel's minions releases VX on a crowded bus, and promises more attacks if the Colonel and Ana aren't released.

Martin is put on leave in the wake of a confrontation with the Colonel. Martin then begins to investigate his own past, discovering that an enigmatic smuggler in Houston may have the answers he needs.

Fallout from a shoot-out finds Martin taking Kyle Dobson into custody. Before long, Dobson's mysterious employers enlist hit men to retrieve a wounded Dobson, prompting Martin to plan a desperate escape with Dobson back to Los Angeles.

Martin returns to DCO after the events in Houston and is presented with the case of a threat to assassinate a visiting Saudi Prince. The investigation leads Martin and Rice to a beautiful and charismatic female rights activist.

Martin stays in legend as journalist Sebastian Egan to exonerate Hani Jabril and find the real assassins of Prince Abdullah. DCO is forced to pursue the investigation 'off book', ultimately leading Martin into his most dangerous stand off yet.

Martin manages to escape from an interrogation and finds out that Sonya and Aiden have been abducted. As he looks for them, he learns more information about his past.

Martin finds out that Verax could be plotting an assassination. He is also kidnapped and makes a stunning discovery about his own identity.