When seven members of their family were kidnapped, thirteen-year-old Dan Cahill and his older sister, Amy, got ready for the fight of their lives. But their enemy, a terrifying group known as the Vespers, remained frustratingly elusive. They stay in the shadows, picking off Cahills one by one.And now the Vespers have landed their most serious blow yet - a blow that strikes at the very heart of the Cahill family. Because Amy and Dan discover that there's...

Amy and Dan Cahill's quest to find the million dollars takes them to Vienna, where they must outwit their power-hungry relatives as they seek to solve a clue involving Mozart.

Vega Jane has never left the village of Wormwood. But this isn't unusual, nobody has ever left the village of Wormwood. At least not until Quentin Herms vanishes into the unknown. Vega knows Quentin didn't just leave, but that he was chased. And he's left behind a very dangerous trail of clues that only she can decode. The Quag is a dark forest filled with terrifying beasts and bloodthirsty Outliers. But just as deadly are the threats that exist...

After seven members of their family are kidnapped by an organization called the Vespers, Dan and Amy Cahill must race against time to track down an ancient map to pay as ransom to bring the hostages home.

At the reading of their grandmother's will, Dan and Amy Cahill are given the choice of receiving a million dollars or uncovering the 39 clues hidden around the world that will lead to the source of the family's power, but by taking on the clues, they end up in a dangerous race against their own family members.