It's not easy having a hungry invisible bandapat living in your laundry basket. It's not easy being the worst swimmer in the fourth grade, either.

And it's really not easy to make pumpkin ice cream taste better than baby food.

Hank Wolowitz is spending all his money on squash for his invisible pal, Inkling, while trying to survive swim class. Meanwhile, back in the family ice-cream shop, Dad sweats unsuccessfully to make a fall flavor that will bring in customers.

Disaster strikes when a truck selling ice-cream whoopie pies parks down the street and starts doing a booming business. Dad goes insane. Mom gets angry. But Hank and Inkling get fired up. Soon they are ready to try anything-a unicorn costume, killing with kindness, a legion of supervillains, anything!-to get Hank's life under control and prevent a full-scale whoopie pie war.