The Rise of Cyrus begins with the problem of succession of the Persian king Darius, who had two children with Parysatis, Artaxerxes and Cyrus. The throne was occupied by Artaxerxes, and a demonic satrap, Tissaphernes, by slandering Cyrus to the new king, accuses him of plotting against his life and Artaxerxes imprisons him. With the intervention of his mother, who loves Cyrus very much, the king releases Cyrus from prison and sends him back as governor to Asia Minor, to the countries around the river Castolus. There Cyrus indeed prepares to claim the kingdom from Artaxerxes.
[...] (from the summary of Book I)