The book also has a subplot in which Bess has fallen in love with one of the cowboys, Chuck, and is worried about whether she should stay and marry him or whether she should remain true to Dave. I remember how traumatized Bess was about the idea of marriage in The Invisible Intruder, so I say that she should dump both of them. She's not ready for marriage!
I was never able to get into this story, simply because I did not care about Roger Paine or Major. I never care as much about missing people and animals when they have not been introduced in the text prior to their disappearance. The book gave me no reason to care.
A burr incident with a horse occurs on page 45, and this incident is just like one from The Secret of Shadow Ranch, 1965 revised text. In both books, an unfriendly cowboy places a burr under the blanket of Nancy's horse.
On page 78, Nancy and Bruce investigate the cloud after Roger Paine's plane disappears into it. They find nothing. Bruce comments, "I guess it's just a hiding place for the sky phantom." Say what? Planes have a continuous forward motion. A plane can't hide inside a cloud for an indefinite period of time.
Bruce flies back into the cloud, and they see a dark cloud inside shaped like a giant. Soon after, the dark cloud reforms into the shape of a lion. The giant inside the cloud is the image used for the cover art of this story. And of course, the cover art is stupid. This is the only Nancy Drew book that has Frankenstein's monster on the cover.
It turns out that a group of revolutionaries have buried weapons in the ground underneath the cloud. This cloud must never move; it's a permanent fixture like a tree.
The revolutionaries even went to the trouble of labeling the boxes so that Nancy and Ned would know that the boxes contain rifles and bombs. How considerate! We wouldn't want Nancy to open a box and accidentally touch a rifle or a bomb!
This is not one of the better higher-numbered Nancy Drew books. While reading, I kept thinking about how the writing of Harriet Adams was noticeably going downhill as these books were published.