In The Double Cousins and the Mystery of the Rushmore Treasure by Miriam Jones Bradley, Carly and Molly go to Grand Rapids, Michigan to visit their double cousin Max and his family. Shortly after arriving, the cousins learn of a local owner Mr. Crosby's tragic story of what happened to his nephew in the Flood of '72. And then Mr. Crosby is in danger of losing his store. The cousins are determined to help! Can they save the store? Only through teamwork and faith will they save the store and solve the mystery---in the process the kids learn an important lesson about community and the value of recording history.