The Cahill family has a secret. For five hundred years, they have guarded the 39 Clues - thirty-nine ingredients in a serum that transforms whomever takes it into the most powerful person on earth. Now the serum is missing. Dan Cahill and his older sister Amy have to get the serum back and stop who stole it...before it's game over. For everyone.

Guardians of the 39 Clues, Dan Cahill and his sister Amy discover that the serum is missing and must race against time to get it back before catastrophe strikes

When the serum of the 39 Clues goes missing, thirteen-year-old Dan Cahill and his older sister, Amy, do whatever it takes to retrieve it.

"LOOT hits the jackpot." -- Rick Riordan, #1 NEW YORK TIMES bestselling author On a foggy night in Amsterdam, a man falls from a rooftop to the wet pavement below. It's Archibald McQuinn, the notorious cat burglar, and he's dying. As sirens wail in the distance, Archie manages to get out two last words to his young son, March: "Find jewels."But March learns that his father is not talking about hidden loot. He's talking about Jules, the twin sister March never knew he had. No sooner than the two find each other, they're picked up by the police and sent to the world's worst orphanage. It's not hard time, but it feels like it.March and Jules have no intention of staying put. They know their father's business inside and out, and they're tired of being pushed around. Just one good heist, and they'll live the life of riches and freedom that most kids only dream about. . . . .Hold on to your pearls, because this summer, the world's youngest criminal masterminds are coming for you.

Fourteen-year-old twins, Roxy and Kaine, have only one thing in common.They HATE each other.Kaine is loud, brash and brilliant at football.Roxy is heading for tennis superstardom.When tragedy strikes, their worlds are ripped apart.Can they come together before it's too late?

When the Vespers continue their abductions and cross a line by kidnapping Atticus, an 11-year-old non-Cahill civilian and Dan's only friend, Dan and Amy confront their biggest challenge ever in order to keep Atticus alive.