One beautiful fall day, Fern opens her mailbox and finds an envelope. After much worrying about what it could possibly contain, her friend Fawn encourages her to open it. Inside, she finds an invitation to a super-special surprise at the museum -- but Fern doesn't like surprises! Luckily, Fawn offers to come with her to the party. What could possibly happen, he asks. Along the way, Fern voices her worries: What if they can't make it in time? What if they don't know anyone there? Fawn playfully follows his friend's way of thinking, while gently suggesting twists to her story and a fun new cast of characters -- the chipmunk who could show them a shortcut, the grumpy bear who could clear their path, the brave dentist who might treat the bear's toothache -- until at last they arrive, and Fern is able to enjoy the wonderful surprise happening around her.