Episode 10A - "Discoveries": Harvey Westerman finds out the group is at the village. He plans to get all of the artifacts he can from the lost city that night, before the group goes there the next day. Meanwhile, back on the Mimi, Pepper and Rosa go on a dive and discover an underground river which opens up into the jungle, where they discover Harvey's henchman and listen to their plans about getting the artifacts out of the lost city. The Maya leader and his son leads the group to the lost city the next day. The group are amazed by this discovery, despite whatever artifacts have been taken by the looters. Expedition 10B - "Up a Tree": Hosted by Carla Dougin. Carla travels to see Monteverde, a tropical forest in Costa Rica. Tropical forests are fantastic places, but they are disappearing fast. Tropical forests are home to thousands of species of plants and animals that have never been studied and exist nowhere else. They could be a new source of knowledge about the earth or new foods and new medicines. The great rain forest near the equator affects the climate and the atmosphere of the whole world. One hundred acres of tropical forests get destroyed every minute. Carla visits with Nalini Nadkarni, a tropical biologist, who studies many aspects of the rain forest to help save them.