Ms. Frizzle takes her class, and Arnold's cousin, Janet, on a field trip to the planetarium. But it turns out to instead be a field trip up into outer space to explore the solar system. However, after blasting off, Ms. Frizzle goes missing after the bus gets hit by a meteor shower. She then contacts her class and tells them how to find her. They'll have to play the games on the planets and moons and win tokens. For each token they find, she will give them a clue. After getting three, the player will have to try to guess which planet or moon she's on.