Sooty and the gang have built a model mountain in the back yard. This gives Matthew the idea to go rock climbing in Snowdonia, Wales. Chaos ensues when Sooty and Sweep pack the wrong things for their adventure into the camper van: a ghetto blaster, among other things. Then Matthew misses the mountain railway train going up, so he has to run after it. When they finally arrive, Sooty climbs the peak of the mountain, prompting Matthew to claim that he could do it just as easily. Then he is told by an experienced mountaineer to climb the much bigger mountain face behind him and he soon ends up dangling from a mountain rescue helicopter.