A life or death quest for water is under way in Tanzania. The Ruaha River is dry and the few remaining ponds are teeming with thirsty, desperate animals. The extreme drought of the savanna has forced an old lioness and her pride to leave the plain in search of food, all senses sharpened. Lions on Edge gives viewers a front row seat to the predator vs. prey struggle for survival in dire conditions. A NatGeo Wild Production.