Emily Byrne struggles to make sense of her time in captivity and her tumultuous past. Meanwhile, a deadly terrorist attack rocks the heart of Boston, drawing Special Agent Nick Durand and the FBI onto the case.

As Nick searches for the Federal Annex attacker, Emily encounters a shadowy figure from her past, whose arrival threatens to shatter her fragile recovery.

Reeling from a shocking loss, Emily must return to the FBI in order to get answers.

Nick’s manhunt for the Federal Annex attacker heats up while Emily and Cal chase down leads on the Fentanyl Killer.

With the Fentanyl Killer’s spree escalating, Emily and Cal fear the next victim will be someone they cannot afford to lose.

Emily and Cal travel to Moldova to track down the Fentanyl Killer – a task that proves to be even more perilous than anticipated.

As Emily and Cal journey into rural Moldova, Nick struggles stateside to swallow a massive lie.

Back in Boston, Emily’s grief gives way to purpose as she discovers a clue that connects Rex Wolfe to the mystery of her captivity.

Emily realizes that Rex Wolf was working for someone connected to both her past and her present.  She finds she can rely on Nick for help, but how to make sense of the puzzle?  Emily resorts to extreme measures when she realizes the threat is close to home.

Emily hits a dead end, but suspects it's not over, and follows the remaining shreds of evidence to a wrenching season climax .