Ep 12. Revelation 6:8

In Highlander: The Series season 5 episode 12 titled "Revelation 6:8", Duncan and Methos find themselves in the midst of a dangerous situation as they attempt to stop a deadly virus from being released. The virus, known as the "Plague of the Third Millennium," was developed by a former Watcher named Vincent and is set to be unleashed on the world.

Vincent is seeking revenge on the world for his daughter's death, and he plans to release the virus unless the world meets his demands. Duncan and Methos race against time to stop him, enlisting the help of a virologist named Rachel MacLeod, who also happens to be Duncan's cousin.

As they work to stop Vincent, Duncan must also confront his own mortality as he grapples with the prospect of dying again and losing his Immortality. Meanwhile, Methos reveals a secret about his past that puts him in danger and threatens to unravel the entire mission.

The episode is filled with tense action and emotional drama, as the Immortals deal with the possibility of losing their lives and the fate of the world hangs in the balance. It's a thrilling installment in the series that showcases the strength of the show's characters and the high stakes of their immortal existence.