Even on beautiful days, bad things can happen. Bad things like Charlotte calling her best friend, Kate, a big pink baby, and Kate crying all the way home. Charlotte feels awful . . . in fact, she feels so awful she can’t even eat her pizza and french fries. It was that bad. Then Grandpa shows Charlotte his invisible mistakecase . . . and she doesn’t believe her eyes! It’s a place where he keeps reminders of all the mistakes he never wants to repeat. Could Charlotte possibly have a mistakecase of her very own?