In the Dinosaur's Paw

It's the first day back to school after winter vacation, and Richard Best is off to a bad start. Who ever heard of a January without any snow? And as usual, he has already forgotten something--the ruler Ms. Rooney had told him to bring for dinosaur day. Luckily Richard finds a ruler in his desk--with a dinosaur's initials--and he's sure the ruler is special. And then he finds out it has magic powers.
All his wishes begin to come true: Snow stars falling, he remembers to do his homework, and the bully Drake Evans gets sick. But now with Drake sick in bed, Richard begins to worry. His only hope is the magic ruler--but it's gone.
What will help him?
From the Trade Paperback edition.