Chasing treasure hunters is not how 12-year-old Annwyn Bradford, her twin sister, Scout, and their neighbor, Eric Larson, planned to spend Spring vacation on the Navajo Nation. They were supposed to help their friend, Ben Lapahie, plan a school science fair. When the school burns down, plans change. While visiting Ben’s grandfather, Anny sees the ghost of an Indian warrior that no one else sees. She fears what people have always said is right: She has an overactive imagination. Only Eric believes her. Their bond is special because Eric is different, too—he’s deaf. When Anny finds a poem on the Internet about the Lost Treasure of the Golden Sun, the two set out to prove that the people who committed this crime are searching for the treasure. The kids unravel the mystery with an unlikely ally—the warrior, who lived long ago. With Anny's psychic powers, her twin's Girl Scout skills, Eric's lipreading and sign language abilities, and Ben's knowledge of the terrain, they follow the ghost's clues through desert mazes, up mountain cliffs, and into secret passages, with the criminals fast on their heels.