After being captured by a group of Delaware Indians and given to their leader as a replacement for his dead granddaughter, twelve-year-old Mary Campbell is forced to travel west with them to Ohio.

For thousands of years, quartz fragments have traveled down the Delaware River (once called the Wehittck by the Lenape Indians), washing ashore near a place settled by the Dutch explorer Cornelius Jacobson Mey, where they are gathered as treasures and known as Cape May Diamonds.