When Wanda discovers that one of Ms. Frizzle's ancestors was Redbeard the Pirate, she naturally wants to follow the treasure map he left. The map leads the class to a coral reef, where they learn first hand that life there is risky. To survive, they find, many plants and animals form surprising partnerships. But Wanda's not interested in partnerships — she just wants to find that treasure! When Ms. Frizzle turns the class into different sea creatures, Wanda as ""Wanda-Anemone,"" ""Wanda-Shrimp,"" and ""Wanda-Remora,"" begins to understand that partnerships are more valuable then she thought.