Last we saw Annie, she had finally defeated Henry Wilcox and was making her escape from Hong Kong. But following that ordeal she didn't return triumphantly to Langley. Instead, she disappeared without a trace.
But now, four months later, Annie is back on the grid and ready to jump in to work. Though CIA protocol would have Annie in debriefs, medical exams and polygraphs for months, she manages with Auggie's help to bypass that and get herself assigned to a new mission: investigating Borz and Mykola Atlan, a pair of Chicago-based Crimean brothers suspected of planning a terror attack.
As Annie heads to Chicago, Joan returns from maternity leave to find that she's been passed over for the promotion to DCS in favor of Calder. That is, assuming Calder can get his personal affairs-which seem to involve a steamy relationship with a mystery woman-in order first. And while Joan heads back to her job running the DPD, Arthur mulls a new job offer from a former student named Ryan McQuaid who now runs a private security firm.
As it turns out, Arthur isn't the only one with a link to McQuaid. Borz Atlan once worked for McQuaid Security, so Annie meets with the Navy SEAL-turned-CEO to see what he can tell her about his former employee. McQuaid doesn't offer Annie much (besides a dinner invitation) but she soon figures out that the brothers' attack will be imminent. Annie's got Borz in her sights, but loses him when she suddenly collapses. Evidently Annie has returned from her months away with a secret-one that could be life or death.
Now, Annie must hide her medical condition from everyone at the CIA-Auggie included-as she scrambles to stop the Atlans. And though she initially suspects that the Atlans are targeting the Chicago Board of Trade, Annie soon realizes that the brothers' plan is much bigger, and much more destructive, than anyone had imagined.