One False Note
One False Note is the second book in "The 39 Clues" series. It is written by Gordan Korman, and was published by Scholastic on December 2, 2008. Following the events of "The Maze of Bones", the protagonists Amy and Dan Cahill learn about Mozart and travel to Vienna, Austria to search for the second clue in the 39 Clues competition. "One False Note" entered the Children's Books New York Times Best Seller list at number one on December 21, 2008 and stayed on the list for children's chapter books for 12 weeks.
The 39 Clues
Thirteen-year-old Dan Cahill and his older sister, Amy, know that a disaster is about to strike the world. They know they are the only ones who can stop it, and they know they may already be too late. The person behind the disaster is their own relative, a man who calls himself the Outcast. He's already re-created two of history's worst disasters, and is only biding his time before he strikes again.