The Sarah Jane Adventures - Season 1 Episode 4

Bea tells Maria that she was once turned to stone by the Gorgon but the talisman can revert the process. It is too late for previous victims but Alan can be saved though there is a deadline. The nuns have the talisman but Luke snatches it from them and destroys the portal which will give the Gorgons access. The Gorgon, actually the Abbess of the nuns' order, is about to remove her veil to petrify Sarah Jane but Maria, using a mirror given her by Bea, reverts the Gorgon's look onto Sister Helena instead, ending the power of the Gorgon. Alan is changed back to himself and his ex-wife Chrissie, who has come to move in with him but generally caused more upset, goes back to her boyfriend.