The second of Carter's Leigh Brackett inspired Mars pastiches offers a similar plot to the first 'The Man Who Loved Mars'. The story opens with Earthling uranium prospector M'Cord rescuing Thaklar, a Martian prince exiled from his nation for betraying a sacred mystery. Together they are forced to join an expedition to discover the truth behind the mystery, each of the party with their own motives and guilty secrets to hide.
This second book is an improvement over the first at least in that the ending is not so contrived and unbelievable. In fact 'The Valley Where Time Stood Still' is one of the best ever efforts from Carter whose fiction output was uneven to say the least.
Using a different cast of characters from the first book, this one can be read as a standalone tale although elements of the Earth/Mars backstory are explained in more detail in the first. ( )