Boom. Fresh off her explosive return to her hometown, Special Agent Emily Slate finds herself facing her worst the possibility of losing her best friend. Agent Zara Foley, Emily's ride or die, has disappeared during an undercover assignment. Determined to stop at nothing to find her, Emily learns Zara was infiltrating a known domestic terrorist cell, one who had recently procured a large cache of explosives. Undeterred, and against her boss's wishes, she joins the team tracking the terrorists in hopes that it will lead them back to Zara. With the clock ticking, Emily must overcome her personal demons and stop butting heads with everyone else on the team if she wants some real answers. But when a series of explosions begin rocking major American cities, Emily will find herself with no one to trust as she tries to uncover the identity of the terrorist a man calling himself Simon Magus. Will Emily find Zara and stop Simon from enacting his final plan before it's too late? Or will she end up in the cinders, like all the rest? Find out in His Final Act.