As Marcus and Sam hunt for the traitor in their ranks who stole their nuclear launch key, Prosser disobeys orders and starts a small war he can't control. Meanwhile Grace and James must work together to defuse a dangerous situation, as back in D.C. Christine is indicted as Sam's co-conspirator.

A visit that will soon turn into a nightmare as Marcus must consider the unthinkable once again. Meanwhile, the true reason for the nuclear devastation in Pakistan is revealed.