Overview: In an attempt to beat Dodo Island, the islanders construct carts to deliver their cargo more efficiently to prospective buyers. All goes well until Olive and Troy, with a cargo of paper, reach a steep hill which they race down uncontrollably. The Inventor helps them add brakes. Meanwhile, Brenda and Pilbeam struggle to get a lovesick mammoth to take a bath. Topics covered: heat, friction, brakes, lubrication.