Against a Crooked Sky

Against a Crooked Sky is a 1975 American Western film directed by Earl Bellamy and starring Richard Boone, Stewart Petersen, and Henry Wilcoxon.
Plot summary.
The eldest daughter of a pioneer family is kidnapped by a mysterious Indian tribe and the eldest son pursues. In order to win back his sister's freedom, he must sacrifice his own life by passing the test of "Crooked Sky" and shield his sister from an executioner's arrow. Along the way, he recruits a broken down, drunk prospector to help him track down the unknown tribe and rescue his sister.
Production.
Parts of the film were shot in Professor Valley, Martin Ranch, Pace Creek, Castle Valley, Dud's Bottom, Arches National Park, Dead Horse Point, and the Dolores River in Utah.
The story was issued in paperback novel, by Eleanor Lamb and Douglas Stewart, Bantam Books, 1976.