I have no idea where this came from, but here it is. There might be more to the story, but if there is, I haven't found it yet. And, as always, none of this is mine.
No spoilers, though familiarity with the Highlander episodes Comes a Horseman and Revelations 6:8 would be helpful.
Kronos grinned maniacally. "Behead me or not, you can't win."
"Think what you like," Duncan growled and swung.
Even during the aftermath, Methos' mind kept circling around those words. He made what peace he could with Duncan then started his search, even before the first deaths, but it wasn't until people started dying in England that he turned to Joe for help from the Watchers. They could find no trace of the methods Kronos had used to create his virus, and Methos gave up to research a cure on his own. It was too late.
The world had moved on.