The Shadow of Light (2002)

A deserted mansion. A hidden journal. A lost wagon train. An obesessed sea captain. A missing treasure. Brothers Jason and Nate Simms may be in over their heads! After a disastrous camping trip, the boys find themselves stranded in a small town with a mysterious past. With the help from the local Mormon bishop and his daughter, Susan, the boys begin unraveling clues that lead them to the pages of the Book of Mormon and a treasure worth more than all the riches on earth.