The Silver Key is the twelfth episode of the series. It aired on 3rd December 1991 in Wales, 24th March 1992 in England and 19th August 1993 in Australia.
Admirable Karia is determined to win The Lock Competition. Meanwhile, Joshua and Joe have trouble with a runaway tyre.
- This was the final episode of the series
- Some video releases call this episode "Silver".