A bottle of nerve manna, a disappearing golf ball and some rocks . . . it all adds up to the Hardly Boys' toughest case yet. The Hardly Boys have returned to Rangeley Lake for another relaxing summer at the Hardly Inn. Fishing, boating, tennis and their friend Chip Mason await them, but the boys soon find themselves enmeshed in a perplexing mystery that puts to the test their sleuthing skills and secret dog powers. What are the Nurse and the Caretaker up to?! And what happened to Gladiola Mason? She invited hem to lunch and now she's disappeared!