The 39 Clues Book 2 One False Note

The journey continues on the search for the 39 clues and Amy and Dan Cahill are completely surprised to find themselves in the lead. They now rush off to Vienna, Italy with only a piece of Mozart's sheet music to help them but they soon get trapped in the Janus headquarters. They are also being chased by deadly relatives who are trying to stop Amy and Dan winning the clue hunt. After realising that the musical notes on the sheet music were also letters they worked out the clue which was TU. Dan had an epiphany and said "it's the old chemical symbol for tungsten!". Amy and Dan remembered the first clue was iron solute and the second clue is tungsten. This is when they realised that this contest is about putting together some kind of formula.

The 39 Clues book1 The Maze Of Bones

Five minutes before Grace Cahill died she changed her will. At her funeral everyone could choose to walk away with one million dollars or begin a very dangerous clue hunt which would reveal the source of their family's power. Amy and Dan Cahill (who are brother and sister) have chosen to start searching for the 39 clues around the world. Their first stop is Paris. The two of them head to the underground catacombs to search for clues which will lead to unimaginable power. There are four branches of the Cahill family, each with their own secrets, abilities and powers. There are the Lucians who are cunning and very good at keeping secrets. Janus have a love of art and are very smart. There are the Ekaterinas who can invent anything and the Tomas branch are very athletic and physical. This is the first book in a series of ten books where a clue to the Cahill family power is revealed as Amy and Dan continue on their clue hunt.