Merlin - Season 1 Episode 12

Gwen's blacksmith father Tom is approached by Tauren, who possesses the alchemist's stone and wants Tom's help in turning base metal into gold – gold he intends using to overthrow the king. The palace guards raid the smithy; Tauren escapes but Tom is caught, sentenced to death for assisting sorcery and (unsuccessfully helped to escape by Morgana ) killed. Appalled by Uther's callousness, she tells Tauren she will help him in his plot, unaware that Merlin is listening. On the pretext of visiting the grave of her father, for whose death she blames Uther, she rides out with the king to lead him into Tauren's trap.