Mirabelle and the Picnic Pranks

When Mirabelle plays too many pranks and isn't allowed at her parents' picnic party, she has a brilliant idea: she'll take a shrinking potion, so she'll be too tiny for anyone to see! But Mirabelle discovers that the garden is a little more dangerous when you're no taller than a blade of grass. Has the mischief gone too far this time . . . ?