S6·E23 Episode 345 (Mon 21st March 1977)

It is the night of the ball in Harrogate and Kathy and Joe are dressed up and determined to enjoy themselves despite Kathy being told by her parents that they don't want to see her again. A night that is meant for enjoyment quickly turns to concern as the two Swedish men, Olaf and Asta, become trapped down a pot-hole. Amongst the concern though is delight for Amos who is called upon by the Hotten Courier to cover the rescue story and is promptly taken to the pot-hole mouth by Henry. After many hours Olaf is dragged above ground with injuries but there is still no sign of Asta.