Lost in the Desert by Anita Ganeri
Boots and Tim have to act fast, they need to take a camera to their Aunt Agatha who is sweltering in the Sahara desert where she's made a fantastic dinosaur discovery. They need your help as they face the danger of dwindling water supplies, stagger through shifting sand dunes, and navigate their way to safety by the light of the stars. You will have Aunt Agatha's diary to give you essential survival tips, and vital information about which animals and plants to avoid. With Aunt Agatha's map to guide you, plot a safe route through the Sahara.