Agnes (The Silvering)
From Tardis Wiki, the free Doctor Who reference
Agnes was a human who lived in Edinburgh during the 19th century. Her brother was Jack.
She and Jack won tickets to see the Silversmith's magic show. Agnes took part in the Silversmith's mirror trick and was replaced by her doppelganger from Mirror Edinburgh. She was put into a cell, from which the Eighth Doctor rescued her from and took her home. (COMIC: The Silvering)