Alfred Hitchcock and Three Investigators--Moaning Cave

[Spectre007]

This was a very enjoyable book. The Investigators are enjoying a vacation at a working ranch when they learn of the legend of a nearby cave. The cave 'moans'. Who is inside the cave and why they are moaning is the main mystery that is to be solved. Throw in the legends of a villainous outlaw from the days of the old west that still rides atop his black stallion and 'The Old One', who is said to haunt around in cave, and you have plenty of mystery and suspense.