S1, E23: Tim’s latest creation is a beautiful, hand-made pop-up book telling a fabulous tale of trees talking in a forest. But Ralphie isn’t buying the premise – trees simply don’t talk! The kids in class take sides, and they all argue until communication breaks down completely. Ms Frizzle suggests they all take a field trip deep into the forest, where the kids can find out for themselves what animals, insects, flowers, and trees all have to say about this! And when Ralphie himself becomes a tree in danger, will he find the words to call for help?