The strange disappearance of a young Turkish client of Mr. Drew's and the gift of an Oriental rug with a coded message woven into its decorative border start Nancy on a difficult search for a missing mannequin. Tracking down the intricate trail of clues takes Nancy and her friends Bess, George, Ned, Burt and Dave to Turkey. Their sleuthing leads them to the Grand Bazaar in the exotic city of Istanbul, where Bess mysteriously disappears. Suspense mounts when Nancy encounters a vengeful enemy at an ancient underground reservoir. Events move swiftly as Nancy and her friends try to solve this challenging mystery, and lead to an exciting climax that will delight and thrill all admirers of America's favorite girl detective.