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 in from around the globe. Cahills are being kidnapped by a shadowy group known only as the Vespers. Now Amy and Dan have only days to fulfill a bizarre ransom request or their captured friends will start dying. Amy and Dan don't know what the Vespers want or how to stop them. Only one thing is clear. The Vespers are playing to win, and if they get their hands on the Clues . . . the world will be their next hostage.

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.

After delivering the last ransom, Amy and Dan discover that Vesper One has a terrifying plot and they race against time to stop him from harming millions of innocent people.

Are you ready to save the world? The bestselling series returns with an adventure spanning 6 explosive books 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 in from around the globe. Cahills are being kidnapped by a shadowy group known only as the Vespers. Now Amy and Dan have only days to fulfill a bizarre ransom request or their captured friends will start dying. Amy and Dan don't know what the Vespers want or how to stop them. Only one thing is clear. The Vespers are playing to win, and if they get their hands on the Clues . . . the world will be their next hostage.

Unable to return to their normal lives despite the end of the Clue hunt, new Madrigal leaders Amy and Dan anxiously prepare for a retaliatory strike by the Vespers, who kidnap a number of Cahill family members and demand that Amy and Dan steal a famous painting.

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.

The explosive finale to Scholastic's mega-selling series. 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, can two kids succeed where 500 years worth of famous ancestors failed?