Twenty years have passed since the goddess Pallas Athene founded the Just City.
The god Apollo is still living among the people there, largely incognito, as a human called Pythias. Now married and the father of several children, the man/god struggles to cope when an unholy tragedy befalls his family. On the surface he handles things in a rational and systematic way - as a god would; but it's evident, particularly to his precocious daughter Arete, that deep down he is unhinged with raw, human grief.
Thus fueled by the bitter desire for revenge, Pythias sets sail for the mysterious Eastern Mediterranean of pre-antiquity. Along with Arete, several of his sons, plus a boatload of other volunteers - the great and now hugely aged Renaissance humanist Marsilio Ficino among them - he hopes to find the man who may have caused his great pain.
What Apollo, his daughter, and the rest of the expedition actually discover - changes everything.