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
After receiving a telegram from the mysterious "NRR", Dan and Amy leave for Russia. Upon their arrival, another hint from NRR leads them to a credit card and false passports belonging to their dead parents. NRR states she is Nataliya Ruslanova Radova, the daughter of the last Romanov, a Cahill. She escaped to live with a low profile. A blood disorder stops her from joining the Clue hunt. Amy and Dan make an alliance with the Holts, and discover a stronghold. It reveals the next clue, Amber.