D.W. wants to be the first person to set foot on Mars, but what if scary purple aliens eat her? Who's responsible for cracking Dad's cake plater and the evidence points to Arthur. The Elwood City Grebes haven't won the Baseball Championship since 1918, and whenever Buster is at the game, the Grebes lose. Arthur finally saves enough money to buy the bike of his dreams, but this new bike is way too nice to actually ride.