Ms. Frizzle is back in action and she has a mission: her students need science fair projects – and fast. What better way to get ideas than to learn from some of the all-time greats? The class heads to the Walkerville Science Museum to see the exhibit on GREAT SCIENTISTS THROUGH THE AGES, where, suddenly, Galileo comes to life! He is about to make a great discovery, but he needs a ride home. Thank goodness Ms. Frizzle knows the way!