You are leading an expedition and come to an impassable mountain range. It looks like a long detour until an old goat-herd announces that there is an opening in the rocks into which the occassional animal wanders, but they never re-appear... See if you can solve the mysteries of Nasty Mountain and continue on your travels. Whether you succeed or fail, you can always try again - but somehow it's not quite the same as before!
Notes
A fairly early game both for the Sinclair ZX81 computer, with 16K memory expansion and also ZX Spectrum, Nasty Mountain (and the more difficult version, Very Nasty Mountain) seems to have involved navigating through seven (randomly generated) dungeons; 16 in the advanced game. Due to the random nature and combat, it's possible that it was more of an RPG than adventure, but object manipulation and text input is mentioned in reviews (such as that in Sinclair User issue 3, June 1982).