The Clue of the Leaning Chimney

As a result of an encounter with a sinister stranger on a lonely country road, Nancy Drew and her friend Bess Marvin discover that a rare and valuable Chinese vase has been stolen from the pottery shop of Dick Milton, a cousin of Bess.
Dick had borrowed the vase from his Chinese friend, elderly Mr. Soong. He is determined to repay Mr. Soong for the loss and tells Nancy that if he can find "the leaning chimney," he feels he will be on the track of a discovery which will solve his financial problems.
Nancy finds the leaning chimney, but it only leads her into more puzzles. Can there be any connection between the vase theft -- one of a number of similar crimes -- and the strange disappearance of the pottery expert Eng Moy and his daughter Lei?