Welcome back to Deckawoo Drive for a sixth endearing installment in the companion series to Kate DiCamillo's New York Times best-selling Mercy Watson books. Frank Endicott is a worrier. He worries about lions, submarines, black holes, leprosy, and armadillos. He lists his worries alphabetically in a notebook and suffers vivid nightmares that even a certain neighborhood pig can't dispatch. When he accompanies Eugenia Lincoln on an errand to duplicate a key at her favorite dark and dusty thrift shop, Frank earns fresh cause for alarm. Odd Buddy Lamp, the shop's proprietor, has sent them home with the original key and its copy. Can Frank come to terms with the mystery without buckling under his mounting dread? With a little help from friends (old and new), hot cocoa, and some classic short stories read aloud, the prognosis is good.