Gold is episode 2 of Mirror Mirror Series 2 and episode 22 overall.
Aunt Lily decides to go through the mirror to try and steal the crown that the de Lutrelle family keeps hidden. Fergus goes through the mirror to try and help Constance, but gets side-tracked by the gold fields. He trades a pocket knife for a claim on a piece of land with one of the miners. After Lily's attempt to steal the crown is thwarted by Daniel and Constance, she moves the mirror when she returns through, leaving both Daniel and Fergus trapped.