Xantho and Penelope are slaves with the great Persian army of Cyrus the Great. Suddenly Xantho and a bunch of slaves are attacked by the Massagetae on the Scythian steppe. Xantho escapes, and goes back to warn his father, a Lord in the army(more on that in the book). The story moves on quickly to find Xantho and a slave girl Penelope, suddenly offered their freedom in the Persian army as part of an elite group. But why? What can two slave offer to a group of Immortals. Its a well crafted story, with a couple of twists. Looking forward to the next instalment.