"Robert Henderson Cahill almost changed history when he came close to collecting all 39 Clues in his secret Indonesia laboratory. However, it was only after a volcanic eruption destroyed his life's work that he realized a missing Clue had been in front of him all along. Since then, tracing the footsteps of Robert Henderson Cahill has led numerous Cahills into danger. Amelia Earhart was looking for his list of Clues during her ill-fated flight around the globe. His Clues were related to the fire that killed Hope Cahill and Arthur Trent. Amy and Dan Cahill weren't able to discover his full list of Clues, but they did find the Clue he prized above all others. And now YOU have it, too!"