Upon her return from Columbia, Annie gets a surprise visit from Arthur, disgraced following his recent revelation of infidelity and resignation from the CIA. Determined to protect his secret connection to terrorist Teo Braga-and most of all to protect Joan from being damaged by it-Arthur asks Annie and Auggie to keep what they know to themselves and help figure out Henry's endgame.
Their investigation soon turns up a connection between Henry and Amstar Oil, an energy company whose business in Columbia has been hurt by recent bombings led by Teo and his terror group. A phone tap also reveals that Henry has an inside man at the CIA feeding him intel, but the mole's identity remains a mystery.
Meanwhile, after Joan asks Auggie to look into Arthur's affair, Auggie discovers that the whole thing was a sham, made up to deflect attention from Arthur's connection to Teo and protect Joan. It looks like Arthur's ruse is working: after Joan aces a polygraph, she learns from former flame Seth Newman that she's up for Arthur's job as DCS. But even more surprisingly, as Annie and Auggie overhear the conversation between Seth and Joan they make a startling discovery: Seth is the mole.
Knowing he has dinner plans with Joan, Annie, Auggie and Arthur decide that Annie should break into Seth's house to try to find proof of his link to Henry. Unfortunately, they can't anticipate that Joan might change her mind, sending Seth home early enough to catch Annie snooping. Or that when he does, he'll do whatever it takes to prevent her from escaping with evidence that could destroy his life...