The Four Horsemen are reunited. Cassandra has been taken prisoner. As MacLeod makes plans to rescue Cassandra and face Kronos for the last time, Methos tries desperately to manipulate all the players so that he can, at least, survive. Kronos' plan is revealed: he intends to use an engineered virus to wipe out most of humanity and conquer the survivors as part of an eternal empire. Methos eventually turns on his former comrades, he and MacLeod simultaneously battling Kronos and Silas to the death in their own respective fights, resulting in a double quickening between MacLeod and Methos.