Lake Tannganyika in Tanzania, East Africa, is the biggest in the world, and is remarkably beautiful. The Tanzanians have two options to cross it: 20 hours on a pickup truck on a road riddled with potholes or 3 days of sailing on the oldest cargo ship in the world, the LIEMBA. On track, traders try to reach the market but torrential rain disrupts the route. The captain struggles to maintain order.