On his way to a party, Mr. Fish bumps into his friend Willa Whale, who is frozen in worry. What if no one wants to talk to her? What if she forgets the words to the birthday song? Using simple steps, Mr. Fish teaches Willa how to breathe and make a plan whenever her worries start bubbling up. After all, worry isn't bigger than a whale! In this newest installment of the New York Times-bestselling series, little guppies will swim with Mr. Fish and his friend as they discover that they can overcome even their biggest worries.