The 39 Clues: One False Note

The story kicks off with the siblings in pursuit of the second clue related to a coded piece of Mozart's sheet music. Their journey reveals that Mozart had a sister, Maria Anna "Nannerl" Mozart, whose stolen diary may hold critical information for their quest. As they explore Vienna's cultural setting, they face challenges from their competitors, notably the wealthy Jonah Wizard and members of their own family, who will stop at nothing to win the competition.
Key plot points include:
Amy and Dan's struggle to recapture Nannerl's diary.
Their adventurous escapades through catacombs, libraries, and museums.
A thrilling escape from Jonah, culminating in a climactic conclusion involving hidden passages and stolen clues.