A treasure map written on buckskin leads siblings to a discovery worth more than gold.Old tropes and new fun greet young readers in a mystery about two kids traveling the powwow highway with their grandparents. Jamie and Marie Longbow are twins. Marie helps Grama make and sell beadwork while Jamie gives Grampa a hand setting up their canvas tent. After finishing one powwow in Massachusetts, they arrive for another in Connecticut, where they are preparing for the grand entry when their grandparents leave them alone for a minute at their booth. Before they know it, they are approached by a stranger who calls himself Lester Laughing. Lester is dressed in old-time regalia. He wears authentic buckskin and carries a big, eagle-feather fan. He stands out due to a scar next to his nose, and he says he knows their family. When he gives them an old map, asking them to keep it a secret from their grandparents, they head off on an adventure with a surprise at the end. Building his story around the trope of the Indian ghost, Abenaki author Bruchac addresses cultural practices in a loving Native family with sweet touches of humor. Deforest, who grew up on the Navajo reservation, gives his characters big, warm eyes and open, cartoon faces that make the illustrations familiar, warm, and friendly. (This book was reviewed digitally with 10-by-20-inch double-page spreads viewed at 30.3% of actual size.)A satisfying story in which two children discover the love of an ancestor. (Graphic/mystery hybrid. 7-10)