Earl gets irate when Mrs. Snodgrass praises Billy and Marcus' model space shuttle as the most ambitious that she's ever seen. Earl hauls out his old model of the solar system and expands it to life size to remind her of his great work. But the planets are all out of order and turn the school into a massive galaxy that's going to hurtle the earth right into the sun! Billy tries to realign the solar system by knocking planets into their proper places with their space shuttle, but he takes short cuts which threaten to ruin the mission. Marcus reins in Billy's rushed effort and calmly figures out a way to divert the sun, sending it crashing into Earl's boiler room! Marcus saves the school, and Billy learns the value of careful preparation and planning.