Why is the river full of red mud? Why won't the horses drink the water and why are the fish dying? Mrs Makoko says that the water is good, but can we believe her? Mpho and her friends decide to find out who is polluting the river, but this is not easy, and it is also dangerous. The readers are graded into three language levels. Each is richly illustrated and includes exercises, questions and an illustrated glossary. Level 1 uses a vocabulary of 600 words.