What would happen if you discovered that your family was one of the most powerful in human history? What if you were told that the source of the family's power was hidden around the world, in the form of 39 clues? What if you were given a choice - take a million dollars and walk away ... or get the first clue? If you're Amy and Dan Cahill, you take the clue - and begin a very dangerous race.

The Outcast recreates the conditions for the Titanic disaster and gives Dan and Amy Cahill just days to stop the shipwreck from taking place.

A Clue found in Book 3 sends Amy and Dan jetting off to find out just what's behind the fierce rivalry between the Tomas and Ekaterina branches of the Cahill family. Was a Clue stolen from the Tomas branch? Where is it now? And most important, can Amy and Dan get their hands on it before their rivals do?

Amy and Dan cross the oceans on the trail of a famous aviator, but they find more than they're looking for. Their enemies are becoming more vicious, and the truths they discover more crushing than ever.

Thirteen-year-old Dan Cahill and his older sister, Amy, are the latest guardians of the Clues -- thirty-nine ingredients in a serum that transforms whomever takes it into the most powerful person on earth. They think they've done everything right, but a tiny mistake leads to catastrophe. The serum is missing and Dan and Amy have to get it back and stop who stole it ... before it's game over.

Throughout the hunt for the 39 Clues, Amy and Dan Cahill have uncovered history's greatest mysteries and their family's deadliest secrets. But are they ready to face the truth about the Cahills and the key to their unmatched power? After a whirlwind race that's taken them across five continents, Amy and Dan face the most the difficult challenge yet -- a task no Cahill dared to imagine. When faced with a choice that could change the future of the world,...

Dan Cahill and his sister Amy travel from the hottest to the coldest regions of the world in order to stop someone from using their own power against them.

Shaken by a shocking loss, Amy and Dan flee to an exotic land and trace the footsteps of their most formidable ancestor yet: a military leader of mythic proportions.

When their beloved aunt--matriarch of the world's most powerful family--dies, orphaned siblings Amy and Dan Cahill compete with less honorable Cahill descendants in a race around the world to find cryptic clues to a mysterious fortune. Includes game cards which the reader may use to play an online version of the treasure hunt.

"Amy and Dan hit the high seas as they follow the trail of some infamous ancestors to track down a long lost treasure. However, the real prize isn't hidden in a chest. It's the discovery of the Madrigals' most dangerous secret and, even more shockingly, the true identity of the mysterious man in black"--Amazon.com.