The Medusa Plot (The 39 Clues: Cahills vs. Vespers Series #1)

Are you ready to save the world? The bestselling series returns with an adventure spanning 6 explosive books, 2 secret-filled card packs, and a website that places readers right in the action.

Thirteen-year-old Dan Cahill and his older sister, Amy, thought they belonged to the world's most powerful family. They thought the hunt for 39 Clues leading to the source of that power was over. They even thought they'd won. But Amy and Dan were wrong.

One by one, distress calls start coming i…