Why Didn't They Ask Evans? Agatha Christie

Was it a misstep that sent a handsome stranger plummeting to his death from a cliff? Or something more sinister? Fun-loving adventurers Bobby Jones and Frances Derwent's suspicions are certainly roused--espeically since the man's dying words were so peculiar: Why didn't they ask Evans? Bobby and Frances would love to know. Unfortunately, asking the wrong people has sent the amateur sleuths running for their lives--on a wild and deadly pursuit to discover who Evans is, what it was he wasn't asked, and why the mysterious inquiry has put their own lives in mortal danger...