The Coming of Arthur (1) (S03E12)

Arthur and Merlin set out on a perilous quest to secure the Cup of Life, a potent magical relic that grants immortality. Unfortunately, they fall into the clutches of Jarl, a ruthless slave trader, before they can obtain the Cup. Just in time, a loyal friend comes to their aid, allowing them to break free. However, with Jarl's assistance, the Cup ultimately lands in the possession of Morgause. Now armed with an immortal army, will Morgause and Morgana finally succeed in their plot to topple Uther?