Part one of two. Methos and MacLeod sense another immortal, and while Methos leaves, Duncan decided to find out who was about.It turned out to be the immortal Melvin Koren, an Comenchero who crossed swords with MacLeod 100 years previously. Another immortal is also about, a 'witch' Duncan met as a child, Cassandra, who turns out to be thousands of years older than MacLeod realized. Cassandra is after Koren, whom she calls Kronos, to settle a score of her own: During the Bronze Age, Kronos led a band of mounted raiders, Imortals called the Four Horsemen. They destroyed her village and enslaved her.
When Cassandra runs into Methos at the dojo, she revealed him to have been one of the Horsemen. After a dramatic confrontation, MacLeod tells him their friendship is over. Methos is forced to join with Kronos to keep his head. He manipulates events as well as he can, and he manages to prevent Kronos and MacLeod from completing their challenge. He throws Cassandra into a river to get her out of the way. When an angry Kronos confronts Methos, Methos reveals that the other two Horsemen are sill alive, he exchanges information on their whereabouts for his life.