The Hidden Oasis opens in 2152 BC with eighty priests setting out under cover of darkness into Egypt's Western Desert, dragging with them a sled on which rests a mysterious object swathed in cloth. Four weeks later, having reached their destination, the priests calmly slit each other's throats. Four thousand years later in present-day Egypt, professional rock climber Freya Hannen arrives for the funeral of her sister, Alex, a Saharan explorer. From...