Little Red Rodent Hood by Ursula Vernon
The return of Princess Harriet! Wielding her sword, saving the day, sometimes even listening to her friend Prince Wilbur's good advice!
A little hamster-girl in a red cloak comes to her and asks for her help against weasel-wolves -- there's a great big one that threatens her poor helpless granny.
But at the forest things don't add up. It involves physics principles demonstrated by swings, a crayon, the Howl every time the moon returns after a new moon, sneezing, fractions, and more.