Over a 10-year period, more than 200 people have disappeared from the area surrounding Tanzania's Lake Tanganyika. At first, the disappearances were attributed to a serial killer or tribal warfare, but scientists eventually discovered that the culprit was a huge, nearly 100-year-old crocodile dubbed "Gustave." This fascinating PBS documentary chronicles scientists' efforts to trap Gustave and move him to a nature preserve before he strikes again.