A deadly plague has struck Olympus. While the Olympians fade one by one, Emily's heart breaks as she watches, particularly when Pegasus begins to slip away. Determined to save him, she embarks on an investigation that takes her back in time to the origins of Olympus and to the deadly battle between the Olympians and the Titans.

In the present, she must face the full force of the CRU. In the past, she must confront Cronus, the father of the gods and leader of the Titans, who is intent on destroying his offspring. When Emily encounters the full power of the flame and a discovery that could change the face of history, will she make the right decisions? And in the race against time to save Pegasus, will Olympus find its true hero?