THE CLASS 3A TRIP TO THE NATURAL HISTORY MUSEUM IS TURNING OUT TO BE A DISASTER: MANY OF KATIE'S EXCITED CLASSMATES ARE ACTING UP, AND THEY TURN ON KATIE AND CALL HER A GOODIE-GOODIE WHEN SHE WON'T JOIN IN! EVEN WORSE, THEIR TOUR GUIDE, MR. WEIR, IS A BIG MEANIE! STILL, WHEN...