The god Apollo, who had chosen to live as a human in the original city, and, having married, is now the father of several children, is struck by a tragic loss, which causes him to become consumed with grief and a need for revenge.

With Arete and several of his sons, Apollo sets out by ship across the Aegean, in the company of sailors, soldiers and scholars, among them the by now 99 years old Florentine renaissance philosopher Marsilio Ficino.

After a long voyage of exploration they discover the sixth, lost group from the City, which has been preaching Christianity to Iron Age Greeks.

[1] Publishers Weekly wrote that Walton succeeded well in showing the impracticality of Plato's ideas, but also thought that her "use of god-level powers, including a book-ending deus ex machina, strips the book of tension.

Walton was, according to Kirkus, in this novel "more audacious ..., launching into her own territory; the plotting and characterization are richer in what begins as a fantasy and then, just at the end, abruptly and intriguingly veers into science fiction."