The Librarians find themselves fighting a war on two fronts. First, Apep, the Egyptian God of Chaos, is released from a museum in Egypt and is revealed to be bent on releasing pure evil into the world to create a chaotic apocalypse. Naturally, the Librarians must stop him...but must do so while also avoiding the new black-ops government agency D.O.S.A. (The Department of Statistical Anomalies). D.O.S.A.'s investigation of magic has the agency--and their determined leader, General Cynthia Rockwell--believing the Librarians are home-grown terrorists.

Accordingly, the Librarians must take on the dual roles of hunter and hunted, as Flynn, Baird, Stone, Cassandra, Ezekiel and Jenkins fight, mission by mission, to save the world...but also get one step closer to losing The Library itself. It's a conflict that forces the Librarians to confront the cost of using magic, as well as their true feelings for each other, this time, once and for all.