MacLeod knew him as Melvin Koren, a desperado who left a trail of death and fire across the Old West, but Cassandra remembers him as an evil far older. He is Kronos, leader of the Four Horsemen, mounted Bronze Age raiders who murdered, raped, and pillaged their way across two continents. Never was a band of Immortals more cruel or more feared. He destroyed Cassandra's people and she's been hunting him across the millenia. But Kronos has a different target now -- Methos.

One by one, Kronos is putting the Four Horsemen back together. Once they struck fear in the hearts of men with sword and axe. Today, their weapons of destruction are different, but their goal is the same: to bring mankind what it fears most, the Apocalypse. Only Duncan MacLeod stands between them and the end of the world.