What is the 39 clues doublecross?

The 39 Clues Doublecross is a book series by Scholastic Inc. and the fourth series in the 39 Clues franchise. The series consists of four books and was released between the years 2015 and 2016.

The story revolves around a group of siblings, Amy and Dan Cahill, their cousins, and other competitors as they continue their hunt for the 39 Clues. The 39 Clues is a powerful, ancient family inheritance that can make the Cahill family the most influential and wealthy family in the world.

In the Doublecross series, the characters face more dangerous and treacherous challenges as a new threat emerges. They must fight against the most cunning and ruthless Cahill enemies to protect their family and heritage.

The series consists of the following books:

  1. Mission Titanic
  2. Day of Doom
  3. The Lost Mission
  4. Countdown

The series also includes additional materials, online games, and collectible cards to enhance the reading and gaming experience.