Presenter and comedienne Sue Perkins follows the course of the river Ganges from its source to the sea. She tells the story of modern India. For 450 million people, the water of the Ganges is essential for food production and industry. But as India's economy continues to grow, the Ganges is under threat more than ever. Sue begins her journey high in the Himalayas at the sacred source of the river and travels through the agricultural and industrial areas of the Ganges Plain. She visits health spas here and delves into the commercialization of Hinduism. Then Sue travels on to the holy city of Varanasi. Here she comes into contact with the death rituals. She also attends a school in Patna, where women are trained to be engineers. To the south, Sue investigates how to protect the Bengal tiger.