The first book refers to Cyrus's secret preparations for his 'March Upcountry' and the battle at Cunaxa in 401 BC, where the Greeks defeat the Persians, but Cyrus gets killed.

The other three books discuss the assassination of the Greek generals in the tent of the scheming satrap Tissaphernes and later Xenophon taking command of the Ten Thousand for their heroic 'retreat' amidst various difficulties, both from the continuous attacks of the enemies and from the hardships through the towering and snowy Carduchian mountains in the dead of winter in 400 BC, until they finally reach Trebizond, shouting 'Thalatta - Thalatta' and humiliating with their salvation the vast Persian state with its millions of soldiers, which could not crush a handful of Greeks within its own territory.