Aquila and the Sphinx

In the concluding volume of the Hugo-nominated Aquila series, Equus Insanus, son of Aquila, is missing for three years as he seeks to bring a villainous Time Criminal to justice, leading his Roman half-brother Lucius to fear the worst. When strange messages reach Lucius, they set off a daring quest that takes them from the pyramids of Giza across the Roman Empire, into space, and through time itself. Filled with satirical humor, the series blends alternate history with adventurous twists as the characters face a final confrontation that threatens the fate of their world.