From the In Search of the Classic Mystery blog:
>Robert Trapett has returned to Snowdonia after a time away. Snowdonia holds terrible memories for him, but he is doing his duty as leader of the 2nd Orton Scout Troop, taking three senior scouts to help them earn their climbing badge, as well as a junior scout – a member of Owl Patrol – too young to climb, but old enough to provide the cooking. One evening on the expedition, as the troop are being regaled by Sir Abercrombie Lewker about his recent trip to the Himalayas, a stranger appears with the news that he has just found a body on the nearby mountainside – a body in an Owl Patrol uniform. But nobody from the troop is missing…

Lewker is holidaying nearby at Dol Afon – the place he was staying at for Death On Milestone Buttress – with his wife and some members of his acting troupe, but when he develops suspicions that the death of the young boy was no mere accident, he and Inspector Grimmett face an impossible investigation. Nobody in either party had a motive to kill the boy or had any opportunity to do so…